Discover Two Bewitching Cameos at the Natural History Museum, London

First published in The Journal of Gemmology Vol.35/No.8, Robin Hansen FGA, gem curator at the Natural History Museum, London, takes us through the gemmological, mineralogical and historical background of two fascinating cameos from the late 1800s.

The collections of the Natural History Museum (NHM) in London include minerals, gemstones, worked objects and carvings. I recently had the pleasure to study two chalcedony/agate cameos that were fascinating for their gemmological, mineralogical and historical interest. What made both so delightful was that they had been carved onto the exterior of geodes. Both were purchased from gem carver Wilhelm Schmidt by the Geological Museum of the British Geological Survey in the late 1800s; the specimens then became part of the NHM collection in 1985.

Wilhelm Schmidt (1845-1938) was born in Idar (now part of Idar-Oberstein, Germany). At the age of 15 he was sent to Paris as an apprentice to learn the craft of gem engraving, under the masterful eye of cameo cutter Arsène. He was trained in the neo-classical style, but stone cameos were going out of fashion when he graduated in the 1860s.

Although Romanticism brought in new trends of Renaissance subjects for cameos, Schmidt's interest waned and he returned to Germany. Following the Franco-Prussia War in 1870 and subsequent events, Wilhelm moved to England with his brother Louis, where he changed his name to William.

The brothers set up a business in Hatton Garden that ran from 1872 to 1915 (Seidmann, 1988). During this time William regularly sold cameos, intaglios and carvings to the Geological Museum. His work was of interest because he utilised more unusual materials such as labradorite, moonstone and opal.


Figure 2. This cameo, also by Wilhelm Schmidt, depicts the head of Jupiter and is carved on the exterior of an agate geode. Specimen BM.1985,M16225; courtesy of NHM London © The Trustees of the Natural History Museum, London.

Of the two cameos documented here, the first specimen is BM.1985,MI5547, described in the museum's handwritten register as 'Cameo in Agate-Jasper on Amethyst' (see cover image). Depicting a Roman man with a wreath on his head, Schmidt carved the layer just beneath the amethyst druse, which consisted of pale orangey pink chalcedony containing fine crisscrossing dark veinlets and a few thin linear arrays of red iron-oxide spots. The layer of chalcedony continues into the background of the carving, giving a halo effect. The amethyst creates a simple dark backdrop, and it is a surprise to most viewers to find the centimetre-sized amethyst crystals on the back-side of the piece.

The terminations of many of the crystals have been ground away, presumably to give the cameo a more even surface. The object measures 78 x 66 x 38mm and was purchased from W. Schmidt on 23 December 1886 for £8. Although no location is given for the source of the raw material, it is likely to have been Rio Grande do Sul in Brazil, well known for its amethyst, agate and jasper, as well as its connections with Idar-Oberstein in the 1800s.

The second cameo, BM.1985,MI6225, is described in the museum's register as 'Head of Jupiter (after the antique) cut on the exterior of a hollow Agate from Oberstein' (Figures 2&3). It is carved as the head of the Roman god Jupiter, with long flowing hair and beard. The agate is very pale purple to light beige and locally contains small, dark, translucent, angular areas. It also has very fine red veinlets and tiny spots with an iron-oxide appearance.


Figure 3. The same cameo by Wilhelm Schmidt showing the rear interior lined by quartz crystals. The raw material originated from Idar-Oberstein, Germany. Image courtesy of NHM London, © The Trustees of the Natural History Museum, London.

On the rear, a fine layering of the agate can be seen around the edges of a hollow geode lined by a druse of sparkling quartz crystals up to 3mm in size that range from colourless to an ever-so-slight hint of pale amethyst. The carving measures 55 x 38 x 27mm and was purchased by the Geological Museum on 25 March 1891 for £10.

Roman figures were a common theme for Schmidt, and the NHM collection includes other cameos that he carved with the head of Mars, several of Minerva and Julius Caesar and a bust of Britannicus.

Reference: Seidmann G., 1988. Wilhelm Schmidt: The last neo-classical gem-engraver. Apollo, No. 317, 12-16.

To find out more about the collections visit nhm.ac.uk.

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.

Cover image and figure 1: In the late 1800s, Wilhelm Schmidt carved this cameo of a Roman figure into chalcedony adjacent to amethyst crystals that originally formed part of a geode. This composite image shows four sides of the object. Specimen BM.1985,M15547, courtesy of NHM London, © The Trustees of the National History Museum, London.


The Fascinating History of Antique Turquoise Jewellery

The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more


Birthstone Guide: Garnet For Those Born In January

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more


Getting Started with Quartz Inclusions

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more


Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more


Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more


Tanzanite: The Contemporary December Birthstone

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more


Birthstone Guide: Turquoise For Those Born In December

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more


Understanding the Cat's Eye Effect in Gemstones

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more


Jade and its Importance in China

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

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Highlights of Gem-A Conference 2019

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

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Additional Info

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Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Garnet is recognised for its rich history as a favourite gemstone of Victorian royalty, Ancient Egyptian pharaohs and the Roman elite. Its painter’s palette of shades, varieties and hues makes it a popular choice for jewellery creations.

Garnet Colours

Garnet is commonly seen in a striking spectrum of red, from orange rust and deep-violet to rich royal reds reminiscent of a pomegranate fruit.

The term 'garnet' comes from the name ‘gernet’, a 14th century Middle English word meaning dark red, further deriving from the Latin 'granatum' meaning 'pomegranate'. This connection was probably made due to the resemblance of garnet crystals to the seeds of a pomegranate.

.
Demantoid garnet with clear horsetail inclusions. Image by Pat Daly.

Today, garnet is the term for a group of minerals found in various colours from the red pyrope garnet to the zesty green tsavorite garnet.

Read more: 5 Things to Consider Before Starting the Gem-A Gemmology Foundation

The range of garnet colours comes from trace metals such as manganese, iron or chromium. Variations in chemical composition between different species of garnet result in a range of hardness on the Mohs scale from 6.5-7.5.

Garnet Varieties

There are five main species of garnet that have the same crystal structure but slight differences in their chemical composition.

• Almandine Garnet: purple to orangey reds
• Pyrope Garnet: purples to orangey reds
• Spessartine Garnet: oranges to yellows
• Andradite Garnet: yellows to yellowish greens
• Grossularite Garnet: colourless to yellow, to orangey red, to vibrant green (rare)

Polariscope garnet peridotite. Image by Pat Daly.

Where Do Garnets Come From?

Garnets are commonly found in many countries worldwide, including Australia, India, Czech Republic, Myanmar, Brazil and Sri Lanka to name a few.

In the 19th century, garnet adorned many decorative creations of the famous jeweller Peter Carl Fabergé and was a gem highly favoured by the Russian royal family. Bohemia and Russia were documented as primary locations to source garnet throughout the 19th century. Today, Tanzania and Namibia are prized for their abundance of garnets.

Left: Spessartine garnet with feather inclusions. Right: Hessonite garnet with crystal inclusions. Images by Pat Daly.

Garnet Folklore and History

Garnet has an extensive history and rich ancient folklore that spreads across many eras. Legend has it that garnet - known as the ‘Gem of faith’ - has powers of good health, prosperity and peace.

Read more: Gem-A Confirm Oldest Known Carved Tourmaline

The bright and striking nature of garnet is thought to be fitting to the vibrant personalities of those born in the month of January. It is thought that individuals who wear this stone can enter the New Year with a sense of renewed purpose, hope and lasting happiness.

Garnet Meaning

This gemstone was once used as a talisman of victory and protection by those going into battle. Many warriors would wear the stone to ward off disease and would place it on their battle wounds as a catalyst for healing.

Read more: Hidden Treasures of the Gem-A Gemstones & Mineral Collection

Historical reference to garnet date back even further to the time of the Ancient Egyptians, who utilised the stone as inlays in their jewellery and decorative carvings. Garnet was also a popular choice for signet rings worn by the Ancient Romans, especially when carved into intaglios to seal important documents. Hailed for its health benefits, garnet was a prized possession for clergymen and nobility across many centuries.

Famous Garnet Jewellery

Today, garnet is used in a wide range of jewellery collections and bespoke pieces such as rings, statement pendants as well as tiaras. Its array of colours and transparency make for spectacular pieces of considerable value.

Read more: The History of Garnet in Antique Jewellery

One of the most famous examples of garnet jewellery to date is a pyrope garnet hair comb from the Victorian era, housed at the Smithsonian National Museum of Natural History. The pyrope garnets that embellish the tiara-shaped comb originated from the Bohemian Mines (now part of the Czech Republic). Rose-cut garnets were often mounted in gold plate or yellow gold - a popular style during the Victorian era.

Whether you are looking for a talisman of prosperity for 2020 or a gift for someone born in January, the fire and sparkle of garnets are timelessly beautiful.

A Malayan garnet with rutile needle inclusions. Image by Pat Daly.

Receive copies of Gem-A’s publications, Gems&Jewellery and The Journal of Gemmology by becoming a Gem-A Member.

What is Associate Membership of Gem-A? Find out here.

Our Short Courses and Workshops at the perfect way to enhance your gemmology knowledge in a short space of time. Find out more here.

Cover image: Almandine garnet with crystal inclusions. Image by Pat Daly © Gem-A.

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Glass Simulants of Gems and Enhancement of Natural Gem Materials in the 16th Century

Guy Lalous ACAM EG, summarises the state of making glass simulants of gems in the 16th Century, as well as exploring the historical information we have available on the enhancement of natural gem materials.

What about gem treatments?

Many gemstones can be treated to alter their colour and clarity. Today, gemmologists are confronted to a broad spectrum of treatments ranging from the simple to the highly sophisticated as well as the easily detected to the highly elusive. Treatments include: bleaching, coating, dying, fracture filling, heating, impregnation, high pressure, high temperature, irradiation, laser drilling and lattice diffusion.

What about the origins of gem treatments?

Heated carnelian was found in Tutankhamun's tomb-dating to at least 1300 B.C.C. Plinius Secundus (First Century A.D) is the earliest written source on gem treatments. Pliny discusses many gemstone-enhancement techniques including foils, oiling and dying that are still in use today, almost 2,000 years later. The "Stockholm Papyrus" made about 400 A.D. in Greek-speaking Egypt contains 73 recipes which deal with the falsification of pearls and gemstones; representing the oldest extended recipe collection dealing with gems. In 1502 "The Mirror of Stones" was published, a fascinating book by Camillus Leonardus, a physician and astrologer of Pesaro, Italy. It discusses gem treatments and simulants and also how to identify those stones that are "not true" and the importance of experience and knowledge in this subject.

In the 17th Century, we have the Gemmarum et Lapidum Historia of 1609 by Boetius de Boot, a physician of Bruges. In the French translation of 1644, there is discussion in Chapters 20 to 22 of the decolourising by heat of sapphire, topaz, amethyst and the like, to produce diamond imitations; the dyeing of stones, mostly with metal compounds, an extended discussion of metal foils and an obscure description on how to harden gemstones. By 1820, agate dyeing in Idar-Oberstein had been perfected to the point that it was practiced on a large scale and the agate sold as treated stone. For the first time, a gemstone material was altered commercially and marketed as such and not as a natural material. By the middle of the 19th Century, gemmology had turned into a science (K. Nassau).

What about man-made glass?

Man-made glass dates back to approximately 5000-4000 BC, this took the form of glazes used for coating stone beads. It was not until 1500 BC that the first hollow glass container was made by covering a sand core with a layer of molten glass. Glass blowing became the most common way to make glass containers from the First Century BC. As from the First Century AD colourless glass was produced and coloured by the addition of colouring agents. Glass has been used as a substitute for emerald and other fine gemstones since at least the days of ancient Rome. Skills for glass making spread throughout Europe and the Middle East when the Roman Empire disintegrated. It was not until the full development of the Renaissance, in the mid-1500s, that a writer purposely gave the tedious details of the entire process of glass 'gem' making. This author was Giovan Battista Della Porta.


Figure 1: These 'emerald' and 'amethyst' glass eardrops in the Renaissance style were presumably assembled in the second half of the 16th century. The mounting is partially silvered copper. The green glass 'gems' are 6 mm in diameter. Courtesy of a private collection near Rome, Italy; photo by Carlotta Cardana.

Giovan Battista Della Porta was the first to publish in print recipes for making glass simulants of gems, in addition to information on the enhancement of natural gem materials. His Magiae Naturalis (1558), originally written in Latin, enjoyed vernacular translations in several European languages. The second, vastly improved edition (Della Porta, 1589), again in Latin, did not enjoy the same popularity - possibly because the first one has saturated the market or, alternatively, because the Catholic Church has enforced rules that made alchemy a forbidden practice and even the title Magiae became suspect. In spite of such restrictions, both editions contributed to making glass 'gems' popular decorative objects and to increasing their trade. During Baroque times, interest in glass 'gem' making reached an acme, and Della Porta's treatise was even translated into English in 1658.

Figure 2: This portrait of Giovan Battista Della Porta at the age of 50 is from the title plate of the 1589 edition of his Magiae Naturalis.

His modus operandi was well known. For every secret he learned, he first checked for other possible sources by reading books by old masters, after which he tested the results by performing experiments in his home laboratory. Glassmaking was one process that could be performed with a kiln, a rather simple apparatus. The preparation of certain special glasses (e.g. coloured ones suitable for simulating gems) involved knowledge that had been an artisan secret until it was released by Della Porta in his original 1558 edition of Magiae Naturalis.

In Book III of Magiae Naturalis, 1558, Della Porta wrote three chapters related to glass that followed the descriptions of other chemical operations, such as sublimation, distillation, purification and melting, plus miscellaneous recipes on how to repair broken corals, pearls and gemstones. He did not care to deal with how to make ordinary glass, but he proceeded directly to release the technicalities on how to prepare the special colourless glass that would be suitable for making coloured glass, so as to imitate gem materials. In chapter 16 he summarised the preliminaries, recommending the use of very finely ground silica mixed with fluxes.

In chapter 17 he made a digression aimed at explaining how natural gem materials acquire their colours and shifted to recipes on enhancing colour by using various natural pigments, by slowly diffusing them from the surface to the bulk of the gem under the slow action of fire. Then he returned to recipes intended to add weight to glass without modifying its hardness. In particular, he recommended adding lead to the already prepared colourless glass only while it melts, so as to increase its brilliance and weight. After another digression, he ended Chapter 18 with a series of explanations on how to obtain attractive 'gem' glass by carefully mixing colourless glass with pigments while it melts. The resulting gem simulants would resemble diamond, emerald, sapphire, pyrope, topaz, olivine, chalcedony, etc. The final recommendation was that the crucible containing the molten mix should be kept under close supervision, as excess heating would make the colour fade away.

In 1589, Della Porta, by now a mature scientist, reworked his Magiae Naturalis, expanding it from four books to 20. The in-folio sized text dealing with gems grew from five ordinary pages to a complete Book VI encompassing 10 dense pages and distributed over 13 chapters. Actually, only Chapters 1 to 5 concern glass gem simulants and Chapters 7 to 13 mostly concern the enhancement of gem materials. Everything is described in much greater detail than in the previous edition. After an introduction, Della Portas begins Chapter 1 with a careful description for the preparation of reagents for glass gem making, beginning with two fluxes. Chapter 2 recalls that silica is the main constituent of any glass gem. The raw silica can be either crystal or flint, or even round pebbles; the best of are said to be those gathered from the river Thames.

Chapter 3 describes in detail the furnace and the instruments to be used and Chapter 4 teaches how to prepare pigments. Chapter 5 is the core of the entire process. Indeed, it is titles "How gems are coloured". The pigments are blended with the previously prepared colourless glass while it is molten, so that they mix homogeneously. The recipe for glass used to simulate emerald is given last because the preparation requires a long exposure to fire. The following chapters describe various enhancements of natural gem materials and then move onto enamels, coloured metal sheets for reflection, etc. The author ends book VI, Chapter 13, with the short but factual statement: "This is all what we experimented on gems so far".


Figure 3: The title page of Magiae Naturalis Libri XX, 1589 edition, shows the titles of all 20 books composing this volume.

The second half of the 17th Century in England was characterised by an economic revival with increasing interest for science in general, including those books penned by 'writers of secrets'. The practice of publishing 'secrets', although unwelcome to many, contributed to the development of both science and the economy. In particular, it is significant that Della Porta's Magiae Naturalis, intended for completely different purposes and contributing only poorly to the 'scientific revolution' because of its still rather alchemical bent, eventually helped speed up the English industrial revolution.

This is a summary of an article that originally appeared in The Journal of Gemmology entitled 'Counterfeiting Gems in the 16th Century: Giovan Battista Della Porta on Glass 'Gem' Making'' by Annibale Mottana 2017/Volume 35/ No. 7 pp. 652-666

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.

Cover image: Title page of the first english translation of Natural Magick in 1658, the title page of Magiae Naturalis Libri XX, 1589 edition and the frontispiece of the english translation of Natural Magick, 1658.


The Fascinating History of Antique Turquoise Jewellery

The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more


Birthstone Guide: Garnet For Those Born In January

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more


Getting Started with Quartz Inclusions

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more


Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more


Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more


Tanzanite: The Contemporary December Birthstone

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more


Birthstone Guide: Turquoise For Those Born In December

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more


Understanding the Cat's Eye Effect in Gemstones

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more


Jade and its Importance in China

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more


Highlights of Gem-A Conference 2019

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more


 

Additional Info

Read more...

Birthstone Guide: Amethyst for Those Born in February

Gem-A gemmology tutor Lily Faber FGA EG explores the history of amethyst and its significance as the February birthstone.

Amethyst is a well-known, purple variety of quartz that is February’s birthstone. Fashioned pieces can vary from a lighter lavender to a deep, saturated purple.

In ancient Greece, it was believed that if worn or used as a drinking vessel, the wearer would be protected from becoming drunk, hence, its name is derived from the Greek words meaning “not drunken”.

Read more: What is the Meaning of Amethyst? 

It is also believed by some that the stone will bring you luck, serve as an antidote to poison, increase your intelligence and protect you from magic spells.


Amethyst quartz with ribbon-like inclusions. Image by Pat Daly.

Various localities include India, the USA, Australia and Brazil, which is one of the most important sources today. Historically, amethyst was mined in Siberia and Saxony (Germany).

Amethysts in History 

In keeping with February’s holiday of St. Valentine’s Day, it is said that St. Valentine wore a signet ring set with an amethyst intaglio carved with an image of Cupid.

Amethyst was also worn in the finger rings of bishops, and can be found in the Crown Jewels fashioned as a faceted orb sitting atop the Star of Africa diamond in the sovereign's sceptre.

Read more: A Quick Guide to the Crown Jewels at the Tower of London


Amethyst quartz with tiger stripe inclusions. Image by Pat Daly.

Historically, aristocratic and royal families the world over have prized the gem in different eras. One such monarch was Queen Alexandra, wife of King Edward VII, who owned a gorgeous amethyst tiara containing several high quality large, oval-shaped stones from the mines of Siberia.

Find Out More! Get Started with the Gem-A Gemmology Foundation Course

She also commissioned a necklace that could also be converted into a tiara. These pieces are sadly no longer in the Royal Collection as they were sold at auction in the 1940s.


Amethyst quartz jewellery set. Image by Pat Daly.

Amethyst Crystals, Inclusions and Colours

If sold as a rough specimen, amethysts are often seen as individual crystals with one broken end where it was detached from the host rock. More often, they are sold in the form of a geode cluster.

Geodes are cavities or pockets that are lined with many crystals of various sizes. Often, the colour is concentrated in the tips of the crystals, thus leading to a great variety in saturation of colour from pale to deep purple.

Read more: Gem Quality Amethyst From Rwanda

An inclusion that is typical, if not diagnostic of amethyst, is the tiger stripe. It is a healed fracture that can occur when the stone twins. Amethysts are either one consistent colour or have angular colour banding with alternating light and dark colour zones.

Amethyst Care and Caution

Amethyst is a relatively hard stone at 7 on the Mohs’ Scale of Hardness, but only just! It is softer than other stones like sapphires, and as such, can be susceptible to chips and fracture.

The colour of some stones can fade when exposed to sunlight, so take care if displaying in a vitrine or shop window. When cleaning, do not use an ultrasonic cleaner in case there are any small inclusions or internal fractures that may expand during cleaning. Use warm soapy water and a very soft brush to clear away dirt.

Read more Gem-A Birthstone Guides here

Do you want to know more about gemstones and the study of gemmology? Discover the Gem-A Workshops or speak to our Education team

Cover image: Amethyst crystal quartz with detachment marks. Image by Pat Daly, Gem-A.


The Fascinating History of Antique Turquoise Jewellery

The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more


Birthstone Guide: Garnet For Those Born In January

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more


Getting Started with Quartz Inclusions

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more


Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more


Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more


Tanzanite: The Contemporary December Birthstone

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more


Birthstone Guide: Turquoise For Those Born In December

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more


Understanding the Cat's Eye Effect in Gemstones

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

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Jade and its Importance in China

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

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Highlights of Gem-A Conference 2019

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

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Coloured Gemstones from Brazil: Past, Present and Future

Guy Lalous ACAM EG presents us a historical review, and an updated overview, of the Brazilian coloured stone industry. His latest Journal Digest from Gem-A’s Journal of Gemmology (Winter 2017. 35.8) also examines the effects of China’s emergence as a consumer market on Brazil’s gem industry.

Recent information on Brazilian gem occurrences is presented from data compiled by the Brazilian National Department of Mineral Production (DNPM) and other resources.

This suite of morganite (16.69–22.22 ct) was cut from Brazilian rough
Figure 1: This suite of morganite (16.69–22.22 ct) was cut from Brazilian rough. The gems were fashioned into various custom cuts, including (from upper left to lower right) Concave, Super Trillion, Deep Concave and StarBrite. Courtesy of John Dyer; composite photo by Ozzie Campos.

The history of Brazilian gemstones began with the early colonisation period. No gem deposits were found until 1573, when emeralds were discovered in the present-day Governador Valadares area. In the late 17th century, the legendary gold mines of Sabarabussu were discovered, located to the east of the present city of Belo Horizonte.

The ensuing rush then expanded north, unearthing the first diamond deposits a few decades later near the town that would become Diamantina. The exploration for gold and diamonds overshadowed other gem mining activities until the 19th century, apart from the Imperial topaz deposits found nearby in the old Minas Gerais capital of Ouro Preto. It was during this time that the term ‘garimpeiro’, which refers to independent miners, emerged.

Germans originating from Idar-Oberstein immigrated to the present-day state of Rio Grande do Sul, and to the north-eastern part of Minas Gerais, after Brazil’s independence from Portugal in 1822. During this period, Idar-Oberstein was experiencing economic troubles as the production from its agate mines dwindled.

The immigrants brought their cutting and polishing techniques with them, and initiated the first stage of development for the modern Brazilian coloured stone industry.

Among the most notable early finds was the 110.5 kg Papamel aquamarine, discovered in 1910 in the Marambaia Valley, as well as numerous emerald deposits. On the eve of World War II, gem-related activities in Brazil were mainly limited to mining, while the end of the war saw the widespread closure of industrial mineral mines in Minas Gerais. Many of these mines turned exclusively to gem production and, accordingly, local lapidary and other trade activities grew dramatically. The latter half of the 20th century was also marked by the emergence of a Brazilian jewellery industry.

What about Brazilian Emeralds?

Emerald is the green variety of the mineral beryl, coloured by chromium and vanadium.  These trace elements are normally concentrated in quite different parts of the Earth’s crust, but complicated geological processes enable these contrasting elements to find each other, and crystallise into one of the world’s most beautiful gemstones.

Geological Processes of Brazilian Emeralds

Brazilian emerald mineralization belongs to the classic biotite-schist deposit, which was formed by the reaction of pegmatitic veins within ultrabasic rocks. The granitic pegmatite injection makes the emerald crystallise at the contact zone between these chemically contrasted rocks.  The pegmatite brings beryllium, while the ultrabasic rock contains chromium and vanadium, and the reaction between them is called metasomatism.  This reaction is, however, only possible when geological fluids are present enough to ensure the transportation of the elements.  Pegmatite-free emerald deposits, linked to ductile shear zones, are also known in Brazil (G. Giuliani).

Weighing 6.11 cm, this emerald is unusually large for clean material from Brazil
Figure 2: Weighing 6.11 ct, this emerald is unusually large for clean material from Brazil. Courtesy of Paul Wild; photo by Jordan Wilkins.

Brazilian emerald production occurs in three states: Goiás, Bahia, Minas Gerais.  The first emerald site in modern times was discovered in 1912 in the deep south of Bahia State, near Brumado. Other emerald discoveries followed in the early 20th century at Ferros, in Minas Gerais; at Itaberaí, in  Goiás and at Anagé in Bahia.

More recent discoveries include: Itabira (1977) and Nova Era (1988) in Minas Gerais; at Santa Terez­inha de Goiás (1981) in Goiás; and in the Serra de Carnaíba region (1983) of Bahia.  Since the 2000s, Brazil has been ranked third among the world’s leading emerald producers, behind Colombia and Zambia.

Paraiba Tourmaline from Brazil

Paraíba tourmalines represented the first recorded instance of copper occurring as a colouring agent in this mineral. The blue-to green colours are primarily due to copper (Cu2+).


Figure 3: The bright coloration shown by Paraíba tourmaline (here, 5.73 ct) as well as its rarity have contributed to its high value. Photo and stone courtesy of Paul Wild.

Paraíba tourmaline—for its singularity and its profitability— became perhaps the most important discovery of the 20th century. Uncovered for the first time in 1987, in the São José da Batalha district of Paraíba, this tourmaline’s unique ‘neon’ blue-to-green coloration contributed to making it one of the most valuable coloured stones on the global market. Production of Paraíba tourmaline has, unfortunately, dwindled in recent years.

Global Gemstone Trade - The Role of Brazil 

In the late 1990s, Brazilian gems were mainly exported to the United States, Europe and Japan, with gem exports to Hong Kong and India increasing too. Finally, another major player emerged: China. The increase in exports of rough gem material to Asia has become very significant and, for a time, most of it was cut and polished in India and China.

Chinese brokers began to arrive in the quartz-producing areas at the beginning of the 2000s. These brokers bought most of the cheaper gems, contributing heavily to a rise in mining activities. Over the years, Chinese dealers acquired a greater variety of stones, showing a preference for tourmaline, especially rubellite.

One consequence of the increasing trade with China, though, has been the collapse of Brazil’s domestic gemstone cutting and polishing industry for low-value materials. The negative effect on local economies is particularly apparent in north-eastern Minas Gerais. In Teófilo Otoni, of the 2,700 lapidary businesses operating in 1993 only 360 remained in 2005. In 2011, China was the main partner in Brazil’s gem commerce, with 2013 seeing Brazil export 60% by weight, or 25% by value, of its output to China (up to 50% by value if Hong Kong is included).

Brazil, however, still remains significant for cutting higher-value gemstones. Teófilo Otoni and Governador Valadares remain the major gem cutting and trading centres. Various urban centres host the country’s main gem fairs, which are small venues compared with other international shows.

An important factor to note is the informal trading of gems; several hundred individuals travel around the country and acquire rough material to sell later in the metropolitan areas. The widespread adoption of modern technology, such as the internet and digital cameras, has revolutionised traditional methods of trading over the past decade, making middlemen somewhat obsolete.

Other factors have also diminished Brazilian gem production, such as the evolution of the international market. Many African countries now produce a larger variety and quantity of gems than they did a couple of decades ago, and those stones are usually sold at lower prices than those from Brazil. The high cost of mining is another reason for the recent decline in mining and production. According to the DNPM, there were 2,294 gem occurrences in 401 different municipalities as of 2013, with 49.3% of them in Minas Gerais and 19% in Rio Grande do Sul.

What about Santa Maria Aquamarine?

One of the rarest and most expensive varieties of aquamarine, the "Santa Maria", has a deeply saturated blue colour, with no hint of green or yellow. Named in honour of Santa Maria de Itabira where these stones were first discovered, the original deposit is now almost depleted, and today most of the Santa Maria colours are also found in several sub-Saharan countries of Africa, including Mozambique.

The colouring process is due to the Fe2+ - Fe3+ charge transfer. This feature is associated with intense absorption and strong pleochroism, and this process cannot be induced by heat treatment. The stones are nearly colourless in the direction of the optic axis, and intense dark blue perpendicular to the optic axis.

Figure 4: This 22.93 ct aquamarine is from Santa Maria in Minas Gerais. Courtesy of Paul Wild; photo by Jordan Wilkins.

Quartz and Topaz from Brazil 

Quartzes are abundant in Brazil. Stunning crystal clusters, appreciated by collectors, come from hydrothermal veins found in the Curvelo and Corinto areas of Minas Gerais. Rose quartz is found in pegmatites in the north-eastern part of Minas Gerais, while rutilated quartz has been produced mainly in the Novo Horizonte District of Bahia State.

Huge amethyst geodes, and most of the agates of the country, have been mined in abundance in Rio Grande do Sul. Citrine is mined there as well, but most of the citrine produced and exported from Brazil is actually heat-treated amethyst.

Figure 5: This large colour-zoned tourmaline from Brazil weighs 144.75 ct. Courtesy of Paul Wild; photo by Jordan Wilkins.

The country accounts for much of the world’s topaz production. Many stones are colourless, or tinged very light blue, and laboratory irradiation creates the bright blue colour. A post irradiation annealing is performed by a heat treatment of the topaz for several hours at around 200°C. The production of the rare and famous orange to orange-pink Imperial topaz has, however, greatly diminished, and good-quality material is particularly scarce on the local market.

Figure 6: The colour of this Swiss Blue topaz (13.73 ct, StarBrite cut) was produced by laboratory irradiation, using colourless or pale blue starting material from Brazil. Courtesy of John Dyer; photo by Ozzie Campos.

More Gemstones of Brazil 

Beryl production is dominated by light to medium-dark blue aquamarine, of which Brazil may be one of the largest exporters, with other beryls including heliodor and morganite. Most production of chrysoberyl is still located in Minas Gerais and Bahiam, but good quality Alexandrite is now harder to find locally and only small quantities are available. Collectively, Emeralds and other beryls, tourmaline, topaz and all types of quartz are the most widely mined coloured stone resources nationwide.

What's Next for the Brazilian Gemstone Industry?

Improved living conditions in rural areas have led to an evolution of the workforce, which is becoming less interested in, and less reliant upon, mining via illicit operations. Brazilian gem exports remain robust and gem mining is seeing a shift toward bigger and more professional companies.

The quantity of mining areas remains substantial and, probably, to a large extent underexplored. Yet, the future of the Brazilian gem industry may depend more on social issues, global market trends and an ability to establish efficient trade relationships.

This is a summary of an article that originally appeared in The Journal of Gemmology entitled '‘Coloured Stone Mining and Trade in Brazil: A Brief History and Current Status’ by Aurélien Reys 2017/Volume 35/ No. 8 pp. 708-726

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.

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Characterising Mexican Amber From the Yi Kwan Tsang Collection

Guy Lalous ACAM EG is on-hand to summarise some of the more in-depth articles from Gem-A's The Journal of Gemmology. Here, he delves into a feature on Mexican amber and the use of FTIR spectroscopy to determine provenance from the Winter 2017 issue. 

Amber is an organic gem. Organic gems are the products of living, or once-living, organisms and biological processes. Amber derives from fossilised resins produced by prehistoric trees.

Such resins are produced by plants in response to certain circumstances, such as defence against insect pests or protection of wounds.The most important resin-producing plant families are classified among the gymnosperms (conifers) and the angiosperms (flowering plants).

The fossilisation process of amber involves a progressive oxidation, where the original organic compounds gains oxygen, and polymerisation, which is an additional reaction where two or more molecules join together. This process produces oxygenated hydrocarbons, which are organic compounds made of oxygen, carbon and hydrogen atoms.  A peculiarity of amber is that it may perfectly preserve an organism in its original life position. 

What about the Yi Kwan Tsang Collection?

This collection consists of 115 amber samples from Chiapas, many of which contain abundant plant and animal fossil inclusions. The ambers were acquired over a 10-year period (~2004–2013) in San Cristóbal de las Casas, Mexico. The collection was displayed in 2015 at the Tucson Gem and Mineral Show and in 2016 at the Beijing International Jewellery Fair. 

FIGURE 1
Figure 1: This necklace from the Yi Kwan Tsang Collection contains amber beads from the San Cristóbal de las Casas area of Chiapas, Mexico, and was made by Francesca Montanelli (Lutezia Jewels, Stradella, Italy). Photo by Francesca Montanelli.

This article characterises Mexican amber from the Yi Kwan Tsang Collection using a variety of methods, including those not very common in gemmology, such as taxonomy studies and mass spectrometry, using techniques optimised for organic molecules. Some of the data was compared to those obtained from amber samples from the Baltic Sea and the Dominican Republic. 

The most important amber mines in Mexico are located in the area of Simojovel, but there are several deposits elsewhere in Chiapas State. They date back to the Late Oligocene/Early Miocene (23-13 Ma).

The area is characterised by three stratigraphic units that contain amber. From bottom to top, these are the La Quinta Formation (28–20 Ma), the Mazantic Shale (23–14 Ma) and the Balumtum Sandstone (16–12 Ma). Most of the amber deposits are associated with lignites, friable shales and deltaic clays in the sandstone. 

There are hundreds of amber mines in the tropical forest around Simojovel, and the amber is mined manually using hammers and chisels. 

The twenty-seven samples examined for inclusions were transparent and typically ranged from golden yellow, orange and orange-red to dark orange; a few pieces were dark brown, and some displayed a little natural green colouration. Internal features consisted of inclusions, as well as less common colour variations and small surface fractures. The fractures are probably related to stress associated with the polymerisation of the resin. 

All of the pieces were inert to short-wave UV radiation but displayed weak to strong fluorescence to long-wave UV. The RI values were constant (1.540), and they were similar to those of Baltic and Dominican amber. Average SG values were found to be homogeneous and relatively low (1.03). 

What about taxonomic classification, taxa and phylum?

Taxonomic classification is a hierarchical system used for classifying organisms to the species level. A taxa is a group in a biological classification, in which related organisms are classified. Phylum is a taxonomic ranking that comes third in the hierarchy of classification, after domain and kingdom.  Organisms in a phylum share a set of characteristics that distinguishes them from organisms in another phylum.   

What about arthropods?

The largest phylum of creatures on Earth without a doubt is Arthropoda, both in terms of number of species and in total number of individuals. There are nearly 1 million species of Arthropods, with over 90% of them being insects. 

The determination of the taxa of the botanical and animal inclusions was difficult because the species that lived in Chiapas during the Oligocene-Miocene were different from the modern ones.

The most important plant inclusions were represented by a petal and a leaflet of the genus Hymenaea, more precisely the species Hymenaea mexicana, which is now extinct. Animal inclusions were more common. They consisted of arthropods such as winged termites and a planthopper. Isolated termite wings were detected as well.

The presence of isolated termite wings is extremely rare and the planthopper species, Nogodina chiapaneca, has only been found in amber samples from Chiapas. It is an extinct species dated to the Middle Miocene, and it lived in a tropical or subtropical climate. The presence of an arthropod of the genus Ochlerotatus (female mosquito) also indicates an aquatic environment.  

Figure 8aFigure 2: (TOP) A flower petal inclusion of the species Hymenaea mexicana (Fabaceae family, Late Oligocene–Early Miocene; Poinar and Brown, 2002 and Calvillo-Canadell et al., 2010) is seen in this Mexican amber sample. The petal measures 1.1 cm long and 0.7 cm wide, and shows a narrow midrib base and basal laminar lobes with a central vein and branches of secondary veins. It appears completely glabrous (smooth). (MAIN ARTICLE IMAGE) The H. mexicana leaflet in this Mexican amber measures 3.3 cm long and 1.1 cm wide. The surface is glabrous and its veins are not visible in this view. Photomicrographs by V. L. Villani. 

FIGURE 11aFigure 3: A planthopper of the species Nogodina chiapaneca (order: Hemiptera, family: Nogodinidae; Solórzano Kraemer and Petrulevicius, 2007) is shown at the bottom of this sample. It measures 11 mm long, and displays a rounded head and a clearly visible thorax with one foreleg. The wings have several veins, but the scales are not preserved. This species is known only from Chiapas amber. Photomicrograph by V. L. Villani. 

FIGURE 12Figure 4: These winged termites and isolated wings (rare in Mexican amber) of the order Isoptera (reclassified as part of Blattodea) were likely trapped at the beginning of the wet season, when termites start to swarm and then shed their wings. The length of the wings is ~1.1 cm. Photo by V. L. Villani. 

What about X-ray powder diffraction?

X-ray powder diffraction (XRD), is an instrumental technique that is used to identify minerals, as well as other crystalline materials.The method is based on the scattering of x-rays by the crystals. X-rays are diffracted by each mineral differently, depending on what atoms make up the crystal lattice and how these atoms are arranged. An X-ray scan provides a unique "fingerprint" of the mineral.

Natural resin/amber is amorphous, so XRD analysis does not yield information on the amber itself but can identify mineral inclusions. XRD identified very small amounts of refikite and hartite, as well as calcite.  Calcite was identified by a diagnostic peak at 3.03 Å (or 29.8° 2θ) in the amber from Chiapas only.  Refikite and hartite have a composition similar to that of resin, but possess a crystalline structure.  They are probably associated with the polymerisation process of the resins. 

What about amber classification?

Amber can be classified according to two criteria: their place of origin, and their chemical composition. When succinic acid is present the amber is classified as succinate, when succinic acid is lacking it is considered as a resinite. 

Mass spectrometry was performed to deter­mine the presence of free succinic acid in the amber samples. Confirmation of succinic acid is obtained from the m/z 117 ion (the negative ion mass peak) corresponding to (M-OH)– of succinic acid. The mass spectrum of the Mexican amber did not show the m/z 117 ion, so the level of succinic acid in this amber was lower than the limit of quantisation (1 ppm by weight), classifying it as a resinite.

The Dominican sample showed a spectrum very similar to that of the Mexican amber, indicating the absence of succinic acid, while the m/z 117 ion was clearly identifiable in the spectrum of the Baltic amber sample.

What about Infra-red spectroscopy and the “Baltic Shoulder” in Baltic amber?

Infra-red spectroscopy is the most effective scientific method for identifying fossil resins.  With this technique, broad absorptions will be witnessed in Baltic amber in the 1260-1160 cm-1 range.  Those are assigned to C-O stretching vibration.  These features known as “Baltic Shoulder” are specific to Baltic amber and are related to the presence of succinic acid. 

Three wavenumber ranges that are important for amber characterisation are 3700–2000 cm–1, 1820–1350 cm–1 and 1250–1045 cm–1; these regions are associated with hydroxyl and carbonyl groups and to C=C double bonds. 

FIGURE 15Figure 15: FTIR spectroscopy of a Mexican (Chiapas) amber shows typical peaks at: 3600–3100 cm–1 (broad absorption band due to the O-H stretching vibration); 2965 and 2860 cm–1 (C-H stretching); 1740 cm–1 (C=O stretching, esters and acid groups); 1450 and 1380 cm–1 (C-H aliphatic hydrocarbons); 1260–1030 cm-1 (C-O stretching aromatic esters and secondary alcohols); and 846 cm–1 (C-C stretching of unsaturated olefins). 

The fossil inclusions observed in Chiapas amber in this study are consistent with a sub-tropical forest and FTIR spectroscopy was confirmed as a useful technique to determine the provenance of the amber samples.   

This is a summary of an article that originally appeared in The Journal of Gemmology entitled ‘Characterization of Mexican Amber from the Yi Kwan Tsang Collection‘ by Vittoria L. Villani, Franca Caucia, Luigi Marinoni, Alberto Leone, Maura Brusoni, Riccardo Groppali, Federica Corana, Elena Ferrari and Cinzia Galli 2017/Volume 35/ No. 8 pp. 752-765 

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.


The Fascinating History of Antique Turquoise Jewellery

The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

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Birthstone Guide: Garnet For Those Born In January

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

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Getting Started with Quartz Inclusions

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

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Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

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Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

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Tanzanite: The Contemporary December Birthstone

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

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Birthstone Guide: Turquoise For Those Born In December

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

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Understanding the Cat's Eye Effect in Gemstones

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

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Jade and its Importance in China

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

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Highlights of Gem-A Conference 2019

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

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Gold of the Scythians: Art, Culture and Techniques

On Tuesday 27th March 2018, Gem-A’s new editorial coordinator, Dr Sarah Bremner, joined a gathering of the Society of Jewellery Historians at the Society of Antiquaries, Burlington House, Central London for their March lecture: ‘Gold of the Scythians: art, culture and techniques’ by the British Museums’ St John Simpson and Aude Mongiatti. Here, she summarises their fascinating lecture.

Those fortunate enough to have had the opportunity to see the BP exhibition 'Scythians: warriors of ancient Siberia', which was on display at the British Museum from 14 September 2017 - 14 January 2018, will have witnessed the exquisite gold craftsmanship of this nomadic culture – but for those who didn’t have the chance this talk was a great opportunity to learn about these ancient nomadic warriors and the spectacular – and probably unexpected – quality of their gold-work.

The Scythians have often been treated as an ‘other’ in ancient sources, such as by Herodotus in his Histories. But unlike our modern concept of history, the Greek word historia (ἱστορία) actually means inquiry – to discover, to learn, to know – and Herodotus’ work is part of a wider movement in Ancient Greek thought that began to ask questions about the world. The Scythians – the subjects of this fascinating lecture – for Herodotus at least, were renowned and different enough to warrant a chapter in their own right in his epic exploration of culture, religion, politics and ethnography. But this was still Scythia from an outsider’s perspective. Since they left no written records themselves, to truly discover the Scythians we must look at their crafts, as it is only through their glittering archaeological record that we can hear their voice and attempt to understand Scythian culture.

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Showcasing select items from the British Museum's exhibition, and some previously unseen objects of the Oxus Treasure, St John Simpson, senior curator responsible for the pre-Islamic collections from Iran and Arabia at the British Museum, opened the lecture with the inspiration behind this exhibition, before providing some historical and cultural context for the fascinating objects that help us to glimpse this nomadic society. 

Offering a great opportunity to introduce the unfamiliar – something the Scythians have been since antiquity – Dr Simpson noted that the British Museum has always sought to tread a new path from other organisations, and when discussing ways to commemorate the 100th anniversary of the Russian Revolution, the British Museum sought to tell a Russian story with Russian Objects, but in a completely new way.

But what story? After reaching out to the State Hermitage Museum of St Petersburg Russia, the British Museum was given access to Peter the Great’s Siberian Collection which was part of the first Russian museum, the Kunstkamera. From this collaboration the Scythian exhibition was designed to showcase the oldest flourishing society of the area that would become Russia, to challenge modern and ancient preconceptions of nomads as uncivilised and, instead, showcase the remarkable skills and craftsmanship of Scythian society. Created for this specific purpose, the exhibition was unique and one of a kind.

Map showing scale of Scythian Territory. Achaemenid Persia in red, Scythians in Light Green. Map produced by Paul Goodhead.

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With a brilliant blend of context and specialist knowledge for his audience, Dr Simpson showed us a map of the Scythian World from the 6th-4th centuries BCE, highlighting the expanse of Scythia stretching from the Altai mountains near China, divided from Achaemenid Persia by mountain ranges and the Caspian Sea, along the Black Sea region to Thrace and the edge of the Greek world. By acknowledging the scope of Scythian territory, we can then appreciate the interactions of Scythian culture with the varied ancient civilisations of the period.

Woman’s shoe. Leather, textile, tin, pyrite crystals, gold foil, glass beads. Burial mound 2, Pazyryk, Altai mountains, southern Siberia, late 4th–early 3rd century BC. Photo © V. Terebenin 2017.

Building on this mix of geography and culture, Dr Simpson explained the importance of understanding the significance of Scythian burial practices; buried in valleys in the summer, Scythian tombs demonstrate a culture that was invested in the afterlife with a sense of permanence, as these underground tombs would freeze over in Winter. This was crucial, as organic remains – which usually perish – have survived in the permafrost, preserved beneath the ice, and so we have a remarkable archaeological record. With a specific example of a 7th century tomb at Tuva – a royal necropolis that Dr Simpson will be excavating later this year – the tomb revealed a high level of craftsmanship and a rich sense of colour. The Scythians scaled up their gold, and created multiple appliques. The clothing itself also showed the spectacular sense of colour and elaborate patterns of Scythian culture – even to the point that the soles of their shoes were highly decorated.

There was also a sense of motion in the gold stitching patterns, creating fluidity in the static items which reflected the physical movement of the body. This motion was also reflected in Scythian body art – where the embalmed bodies preserved elaborate tattoos. The designs on wooden coffins, on gold objects, and on the appliques in fabric clothing continued across the body where an animal-combat motif would have moved with the human body itself, creating layers of style and meaning across both gender and status.

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Gold plaque with hare hunt. Kul’ Oba, northern Black Sea region, first half of the 4th century BC. Photo © V. Terebenin 2017.

Dr Simpson then highlighted the significance of the horse – heavily-featured in Scythian gold art – to their society. By successfully domesticating horses, the Scythians revolutionised their society in a way comparable to the Industrial Revolution in Britain. Not only did this transform warfare, but significantly altered the speed of transport. Transport enables trade, and new trade routes, and this new reach likewise creates a transportation of ideas and new technologies, and we see this in Scythian craftsmanship. From this interaction with other cultures we see the inclusion of lions, the apex predator of Persia and a predominant feature of Achaemenid art, in Scythian clothing where we have appliques of lions, and even roaring lions turned into felt work.

Dr Simpson concluded his half of the lecture by noting that history has often approached the Scythians through the lens of others, and then in the 2nd Century CE the Scythians simply disappear. To try and understand what happened, we need to turn to archaeological science, as we can only hear their own voice through their crafts, and their gold-work helps us create a sense of Scythian identity.

Dr Simpson then handed over to Dr Aude Mongiatti, department of conservation and scientific research, who discussed manufacturing technology of the animal-style gold work in the collection. Dr Mongiatti, who works on non-ferrous metal artefacts and ancient metallurgical technologies at the British Museum, specialises in material such as crucible remains associated with metal production. Her research team focused on three non-invasive techniques to examine select items of the Scythian collection:

  •  Optical Digital Microscopy
  •  Scanning Electrons Microscopy (SEM) to get accurate images of the 3D objects 
  •  X-Radiography, at high levels of 450 Kr to get through the gold and the bronze


These methods are used to identify the composition of metals and alloys, and to identify the techniques used to produce objects, and were applied to 15 objects from the Hermitage collection, and 8 objects from the Oxus Treasure, consisting of gold belt-plaques made by casting and some by hand. 

Read more: As Transparent as a Diamond? Why blockchain technology is making headlines

Dr Mongiatti highlighted the casting surface texture of these items, revealing Scythian manufacturing techniques and processes (which included repoussé, chasing and punching) and also the intricate stone and glass inlays which featured the reuse of gemstones. There was a consistent theme of animal motifs in these objects, and an interesting discovery via the microscopy which revealed dot-impressions used to outline the designs. Yet there was also nothing standard or consistent when it came to attachments, but rather the collection displayed a variety of approaches.

Through digital and radiographic examination, Dr Mongiatti also found unusual textile impressions on the back of some cast belts, and currently we do not know why this occurred. She welcomed any ideas on this, and my own guesses include the possibility that textiles were used in the casting process – or that the textiles had a role in transferring designs – or human error.

Dr Mongiatti then showed us examples of hand-worked sheet metal – which had a strong shine, and demonstrated a more Western Greek/Persian influence compared to the cast-examples. Scientific testing also revealed that some of these objects were hollow, as demonstrated in the X-radiography testing on this Fluted Bowl of 5th-4th century BCE with hammered rivets, which clearly shows that the feline handles are actually hollow and made of two halves which are then attached to the bowl.

This fascinating lecture concluded with a brief Q&A and a drinks reception. I would like to thank the Society for inviting me as a guest to attend this lecture.

The oldest society in the world dedicated to their subject, the Society of Jewellery Historians runs an annual programme of lectures throughout the year, from September to June, with a list of national and international speakers. For future lectures visit: www.societyofjewelleryhistorians.ac.uk/current_lectures 

Cover Image: Gold plaque of a mounted Scythian. Black Sea region, c. 400–350 BC. Photo: © V. Terebenin 2017

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.

Dr Sarah Bremner is the editorial coordinator at Gem-A and has a PhD in Classics, Ancient History and Archaeology, specialising in Classical Greece and Athenian Democracy.

 


The Fascinating History of Antique Turquoise Jewellery

The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more


Birthstone Guide: Garnet For Those Born In January

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more


Getting Started with Quartz Inclusions

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more


Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more


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Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more


Tanzanite: The Contemporary December Birthstone

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more


Birthstone Guide: Turquoise For Those Born In December

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more


Understanding the Cat's Eye Effect in Gemstones

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more


Jade and its Importance in China

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more


Highlights of Gem-A Conference 2019

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more


Additional Info

Read more...

110 Years of Gemmology

It all started with an idea...

Manchester, England, 1908
110 years ago today, on July 6 1908, Samuel Barnett a jeweller from Peterborough, stood up at a gathering of the National Association of Goldsmiths to propose an idea: to offer lessons and examinations in gemmology to support the jewellers’ industry. 

The UK’s leading goldsmiths and jewellers supported the idea and created an official committee to advocate gemmological education. In that moment, Barnett established the UK as the world’s first provider of gemmological education, and became the father of what would one day become Gem-A. As another Gem-A founding father, Basil Anderson, noted many years later, Barnett’s proposal "marked the beginning of organised gemmology, not only in this country, but in the whole world".

 
G.F Herbert Smith

This was an exciting time of innovation in the gemmological world. The years building up to Barnett’s proposal had already seen the arrival of the Steward Refractometer in 1905, followed by the Goniometer and Spectroscope in 1907. Renowned mineralogist Dr G.F Herbert Smith was also developing his ground-breaking book Gemstones, released in 1912, offering the first textbook on gemstones with full instructions on how to use specialist equipment. While the gems and jewellery industry was an ancient trade, this equipment enabled jewellers to now look inside their stones, and these years mark the first advances in practical gemmology.

London, 1913
Within five years of Samuel Barnett’s proposal the first gemmological examinations were held, set and marked by Herbert Smith, with Barnett himself receiving the first ever Diploma in Gemmology. 

Since 1913, gemmology has gone from strength to strength, with the continued ethos of serving the industry through championing access to gemmological education.

In 1938 we officially became the Gemmological Association of Great Britain, and over the last century we have seen a prestigious line of Gem-A presidents, including internationally renowned gemmologists, inventors and even Nobel Prize winners. Over the next coming months our 'Heritage Series' will showcase these Gem-A Greats and their contributions to the advancement of gemmology and the wider scientific community.

From an idea in 1908, today Gem-A’s Gemmology and Diamond Diplomas are taught in 40 Accredited Teaching Centres across the world and our FGA and DGA members are internationally recognised by the industry.

Between now and the Gem-A Conference in November we will be celebrating the last 110 years of gemmology and our proud history of being the world’s first provider of gemmological education. So keep an eye out for the latest 'Heritage Series', where we will explore our illustrious founders, including Herbert Smith, Basil Anderson, and Sir Lawrence Bragg.


Gem-A Graduates 2017

 

If you would like to join us in celebrating 110 years of gemmology education click here and register for the Gem-A Conference 2018.

If you are a Gem-A Member or Student you will receive an email with an access link, if you haven't received it please contact membership@gem-a.com.

 


The Fascinating History of Antique Turquoise Jewellery

The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more


Birthstone Guide: Garnet For Those Born In January

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more


Getting Started with Quartz Inclusions

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more


Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more


Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more


Tanzanite: The Contemporary December Birthstone

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more


Birthstone Guide: Turquoise For Those Born In December

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more


Understanding the Cat's Eye Effect in Gemstones

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more


Jade and its Importance in China

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more


Highlights of Gem-A Conference 2019

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more


 

Additional Info

Read more...

Sir Henry A. Miers - Gem-A's First President

'Curiouser and Curiouser', said the Gemmologist

On July 6, Gem-A celebrated the anniversary of 'organised gemmology education', the idea proposed by Peterborough jeweller and one of Gem-A's founding fathers, Samuel Barnett. For the second instalment of our Heritage Series we turn to Gem-A's very first president, Sir Henry A. Miers F.R.S, the eminent mineralogist and crystallographer who became Gem-A president in 1932.

In his lectures for the Royal Society in 1896 on ‘Precious Stones’, Henry Miers aimed to highlight the importance of considering, not just the history or artistic interest of gemstones, but some of their more curious properties.

By examining their refractive index and specific gravity, Miers demonstrated how instruments such as the goniometer, refractometer, dichroscope, and polariscope helped to determine the identity of gemstones beyond opinion to scientific proof: ‘the methods are those of physical science – and they are accurate’ (Miers 1896, Scientific American, 17309)


From the 'Precious Stones' article  (Miers 1896, Scientific American, 17309)

Observing the number of serious mistakes made in the jewellery trade in the 1890s, Miers despaired that ‘the jeweller’s trade stands almost alone…in ignoring the aid of physical science’ and in these lectures, published in Scientific American, he championed the ‘absolute necessity of accurate scientific knowledge’ to identify gemstones (and their imitations).

Graph detailing SG and RI from the 'Precious Stones' article  (Miers 1896, Scientific American, 17309)

In just over a decade’s time in Manchester July 1908, Samuel Barnett would propose the establishment of organised gemmological education to the National Association of Goldsmiths, and Miers’ call for applied gemmology in the jewellery industry would become a reality.

Read more: 110 years of Gemmology

For Miers, those fortunate enough to delve into the world of gemmological science were intrepid explorers, and in their ‘attempt to explain all these curious properties, will find themselves in a most fascinating field of discovery and speculation.’ (Miers 1896, Scientific American, 17309)

It was a world that Miers remained in for his entire life.
A King’s Scholar of Eton College, the young Henry went to Trinity College, Oxford, on a classics scholarship, before transferring to mathematics. From Oxford, Miers joined the Mineral Department of the British Museum (Natural History) under Lazarus Fletcher in 1882 and – like many of his Gem-A successors – went on to become Keeper of the Minerals.

At the British Museum, Miers arranged the mineral gallery and the crystallography catalogue, while also lecturing in crystallography at Central College, South Kensington, and publishing his research on precious stones and the morphology of various minerals.


Gem-A's collection of Miers' work

Remaining in the fascinating field of discovery that is gemmology, Miers was offered the Chair of Mineralogy in 1895 at Magdalen College, and on his return to Oxford he improved their laboratory and the University’s mineral exhibition. Miers was also made a fellow of the Royal Society in 1896 and in 1902 published his seminal work Mineralogy: an introduction to the scientific study of minerals, before becoming president of the Mineralogical Society for 1904/5.

Read More: Gem-A History 1908-Present

In 1912 he was knighted, and in 1915 became the Vice-Chancellor and Professor of Crystallography at Manchester, which under Ernest Rutherford became a hub for nuclear physics and crystallography, attracting the likes of the Nobel Prize Winner Sir Lawrence Bragg - who likewise would go on to become Gem-A president!

Sir Henry Alexander Miers, Gem-A's President 1932-37.
National Portrait Gallery, London, Creative Commons.

In 1926, Miers returned to London and became a trustee of the British Museum. He was appointed to the Royal Commission for National Museums and Galleries, a role that took him around the UK and the world: the Carnegie UK trust invited him to report on museums across Britain, and then for the Carnegie Corporation in New York. He went on to Canada and British Africa in 1932. It was at this time that Sir Henry was approached to become the first president of the (then) Gemmological Association, a post he held until 1937.

Printed Works of Gem-A Greats featured in our 2018 Heritage Series. 

Sir Henry Miers died peacefully at home on 10 December 1942, aged 85, as arguably one of the first trailblazers of gemmology. He was held in such high esteem that it was the equally renowned Dr Herbert-Smith who wrote his obituary in Nature. It is to Herbert-Smith we will turn to in our next instalment of Gem-A’s ‘Heritage Series’.

If you would like to join us in celebrating 110 years of gemmology education click here and register for the Gem-A Conference 2018.

If you are a Gem-A Member or Student you will have received an email to book member or student rates, if you haven't received it please contact membership@gem-a.com.

Cover Image: Sir Henry Alexander Miers by Lafayette, whole-plate film negative, 30 May 1929, NPG x69585 © National Portrait Gallery, London, Creative Commons. 


The Fascinating History of Antique Turquoise Jewellery

The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more


Birthstone Guide: Garnet For Those Born In January

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more


Getting Started with Quartz Inclusions

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more


Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more


Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more


Tanzanite: The Contemporary December Birthstone

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more


Birthstone Guide: Turquoise For Those Born In December

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more


Understanding the Cat's Eye Effect in Gemstones

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more


Jade and its Importance in China

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more


Highlights of Gem-A Conference 2019

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more


 

Additional Info

Read more...

Dr Herbert Smith: Innovator, Inventor, Gem-A President

Dr Herbert Smith was Gem-A President from 1942 until 1953. He was integral in the development of gemmology for the jewellery trade and had an extensive list of accomplishments throughout his career and tenure as president: 
- He developed the Herbert Smith refractometer which, as Noel Heaton noted, improved the instrument beyond recognition and provided the industry with a means to determine the refractive index of a gemstone in a matter of seconds (without even needing to remove it from a setting).

From Nature 25 May 1911 

- He not only discovered a new mineral (paratacamite), but also has one named after him (Herbertsmithite).

- His seminal work Gem-Stones 1912 is well known to students and jewellers alike, as the first text book on gemmology with full instructions on how to use specialist equipment.

- Maybe you are are Gem-A student or graduate who has studied in the Herbert Smith room here at Gem-A HQ in London.

- You may have even bought a postcard featuring collections from the British Museum – this idea was born from Herbert Smith and is a tradition that continues today.

READ MORE: 110 Years of Gemmology

Mineralogy at the British Museum (Natural History)
Like Henry Miers before him, the young Herbert Smith went to Oxford – specialising in mathematics and physics, and then likewise went on to join Sir Lazarus Fletcher’s Department of Mineralogy at the British Museum (Natural History) in 1897 where he soon specialised in crystallography and in the use of instruments to identify faceted gemstones.

Through this work he invented the three-circle goniometer and designed an updated refractometer which, in doing so, ‘put in the hands of jewellers an instrument that all could use effectively with very little difficulty’ (W. Campbell-Smith). 

Demonstration of the Herbert Smith Refractometer in the 1912 'Gem-Stones'

In 1912 Herbert Smith published the pioneering work Gem-Stones, which was the first systematic approach to gemmology, and importantly, accessible gemmology. As he noted in his preface:

‘If this book be found by those engaged in the jewellery trade
helpful in their everyday work, and if it wakens in readers generally
an appreciation of the variety of gems, and an interest in the wonderful
qualities of crystallised substances, I shall be more than satisfied’

(Gem-Stones 1912: viii)

READ MORE: Gem-A's first President: Sir Henry Miers

Legacy at Gem-A
Maintaining this purpose, when the National Association of Goldsmiths enacted Barnett’s 1908 proposal for gemmological examinations, it was Herbert Smith who set and marked the first Gemmology Diploma, he remained at the core of the educational committee that became the Gemmological Association in 1931. 

The Gemmology Diploma examination from 1933, marked by Herbert Smith

To this day Gem-Stones is a gemmological treasure and its multiple editions have involved contributions from some of the other stalwarts throughout Gem-A history including: R.Webster, B.W Anderson, G.F Andrews and G.F. Clarringbull.

Various editions of Herbert Smith's 'Gem-Stones' from the Gem-A Collection

Herbert Smith went on to become Gem-A president in 1942, succeeding the Nobel Prize Winning crystallographer Sir William Bragg, and remained so until his death in 1953.

READ MORE: Journal Digest: Delve into the Colours of Rainbow Lattice Sunstone

During this time he was also – like many of Gem-A's previous Presidents – Keeper of the Minerals at the British Museum (NH), and he spent much of his professional life in service to the Museum. He championed inclusivity and outreach through his work with Gem-A, the Civil Service Arts Council, the Society for the Promotion of Natural Reserves, and the Wild Plant Conservation Board. He was also a part of the British delegation to the International Conference for the Protection of Nature at Bruunen in 1947.

Handwritten dedication by Herbert Smith in his 'Gem-Stones' to his daughter Jeanne
May 1912

He was a fellow of the Royal Astronomical Society, a member and vice-president of the Mineralogical Society, a fellow of the Geological Society and a member of the British Association. To top it all off, in 1949 he was awarded a CBE.

It is fair to say that without Herbert Smith, Gem-A and gemmology as we know it today would not have been possible. He was a pioneer of gemmology for the jewellery industry, a Gem-A examiner from 1913 to 1951 and he cultivated knowledge throughout his life and shared it with others.

READ MORE: Gem Empathy Competition Returns for IJL 2018

If you would like to join us in celebrating 110 years of gemmology education click here and register for the Gem-A Conference 2018.

If you are a Gem-A Member or Student you will have received an email to book member or student rates, if you haven't received it please contact membership@gem-a.com.

Cover Image: Portrait of Herbert Smith, which hangs in the Herbert Smith Room at Gem-A HQ in London.


The Fascinating History of Antique Turquoise Jewellery

The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more


Birthstone Guide: Garnet For Those Born In January

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more


Getting Started with Quartz Inclusions

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more


Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more


Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more


Tanzanite: The Contemporary December Birthstone

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more


Birthstone Guide: Turquoise For Those Born In December

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more


Understanding the Cat's Eye Effect in Gemstones

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more


Jade and its Importance in China

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more


Highlights of Gem-A Conference 2019

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more


 

Additional Info

Read more...

Leading the World's First Gemstone Testing Laboratory: Gem-A's Basil Anderson

As we build up to the Gem-A Conference 2018 in November, we are continuing our celebration of the Gem-A Greats who have been pivotal in our history. This week’s Heritage Series turns to another of Gem-A’s founding fathers, Basil Anderson.

Basil Anderson with X-ray equipment. Image Credit Gem-A.

At a time when the gemmological world and the jewellery industry were rapidly changing with new innovations and the appearance of sophisticated synthetics, Basil Anderson was a pivotal figure in ensuring the link between gemmological science and industry-practice. His commitment to maintaining the important relationship between gemmologist and jeweller is still at the heart of Gem-A’s educational ethos to this day.

READ MORE: Heritage Series, Dr Herbert Smith 

Educated at Kings College London, Anderson graduated with a first class degree in Chemistry and Mineralogy in 1924. That same year he was introduced via his professors to Mr Tanburn of Hatton Garden, who was actively looking for someone to run the world’s first gemstone testing laboratory.


Original Notes from Anderson's colleague CJ Payne at the Testing Laboratory. Image Credit Gem-A

This was a critical time for the gemstone and pearl industry. With innovations such as Mikimoto’s development of cultured pearls in 1921, the jewellery industry was in a transitional period as it responded to the impact of synthetics on the industry.

In direct response to this new crisis, the London Chamber of Commerce created the ‘Diamond, Pearl and Precious Stone Trade Branch’ – with the aim of creating a laboratory to authenticate gemstones and pearls. The recently graduated Basil Anderson, much to his own humble surprise, was the ideal candidate, and in his 1981 lecture to Gem-A he recounted how he ‘toddled along’ to Hatton Garden for his interview. It is safe to say Anderson was successful, and following an all-important cup of tea, he began running the world’s first gemstone testing laboratory.

Collection of Anderson's Laboratory Notes from 1925. Image Credit ©Gem-A.

For Anderson, the jewellery sector was a “very ancient trade and it has always been a very honourable trade”, and the appearance of mass synthetics was “innocuous” because the chain of confidence – from miners to dealers to lapidaries to manufacturers to retailers – was shaken by the introduction of synthetics.

READ MORE: Birthstone Guide, Spinel for those born in August

So while Gem-A was created out of a need to provide gemmological education for the jewellery trade in 1908, the first gemstone testing laboratory was likewise created out of the need for gemmological knowledge and scientific authentication to safeguard integrity.


Original and latest editions of Anderson's Gem Testing.

Indeed, the very title of his 1942 book Gem Testing for Jewellers crystallises Gem-A’s ethos of providing gemmological knowledge to support jewellers, and of expanding gemmological science to reach jewellers, traders and the developing gemmological community. In the book’s original preface, Anderson stated it was intended “to reinforce the invaluable knowledge which the jeweller has gathered by virtue of long experience, to reinforce this knowledge by making it more conscious and giving it a firmer factual basis”.

READ MORE: Journal Digest, Rainbow Lattice Sunstone 


The Chelsea Filter, patented by Gem-A

LEGACY
Anderson ran the testing laboratory from 1924-79 and soon became the preeminent expert on pearl authentication of his day. While teaching Gem-A’s Gemmology Diploma, Anderson invented the Chelsea Colour Filter in 1934 with his colleague CJ Payne and the students at Chelsea Polytechnic, which is still sold today by Gem-A Instruments and used worldwide.

Early Advert for the Chelsea Colour Filter

Anderson became our head examiner 1951, succeeding Dr Herbert Smith, and was later voted in as Vice President in 1976.

READ MORE: Gem Empathy IJL Competition 2018

Anderson understood and advocated the importance of science and experience working together to the benefit of all in the gemmological and jewellery industry, so that traders were not hazarding opinions but could make informed factual analysis. Basil Anderson’s legacy to Gem-A can be seen in the laboratory named for him at Gem-A HQ in London, and in the annual awards in his honour at Gem-A graduation: the Anderson Medal, awarded for the best set of papers on the Foundation examination, and the Anderson/Bank prize for the best Gemmology Diploma theory paper. In 2013, Anderson was named in the French Association of Gemmology’s 50 most influential gemmologists of all time.


Basil Anderson, Image Credit Gem-A

As we look forward to the Gem-A Conference and Graduation this November, those graduates who are awarded the Anderson medals become a part of our proud history, together with our founders who helped to shape the gemmological world of today. 

If you would like to join us in celebrating 110 years of gemmology education click here and register for the Gem-A Conference 2018.

If you are a Gem-A Member or Student you will have received an email to book member or student rates, if you haven't received it please contact membership@gem-a.com.

Cover Image: Photographs of Basil Anderson in the Gem-A collection. Image Credit Gem-A


The Fascinating History of Antique Turquoise Jewellery

The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more


Birthstone Guide: Garnet For Those Born In January

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more


Getting Started with Quartz Inclusions

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more


Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more


Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more


Tanzanite: The Contemporary December Birthstone

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more


Birthstone Guide: Turquoise For Those Born In December

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more


Understanding the Cat's Eye Effect in Gemstones

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more


Jade and its Importance in China

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more


Highlights of Gem-A Conference 2019

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more


 

Additional Info

Read more...

Heritage Series: The Trailblazing Efforts of Robert Webster

Our Heritage Series celebrates some of the most prominent figures in Gem-A's History who have helped to shape the world of gemmology today. Listed in the French Association of Gemmology's '50 Most Influential Gemmologists of All-Time', this instalment turns to Gem-A's most prolific writer: Robert Webster.  

Born in 1899, the young Robert Webster left school at the age of 15 to support his widowed mother, and his father’s footsteps as a pawnbroker. As Basil Anderson notes in his touching obituary to Webster, this proved to be a valuable training ground for the practical gemmologist.


Webster and his Gemmology Class © Gem-A

During the First World War, Webster was awarded the Military Medal for his bravery in carrying messages under fire, and on returning to England he began studying gemmology at Chelsea Polytechnic under Mr I.G Jardine. It was here in 1933 that Webster met the recently appointed lecturer in gemmology, Basil Anderson, at a time when the gemmological world was, in Anderson’s own words, “advancing on all fronts”.

Webster soon became a regular contributor to The Gemmologist (predecessor to The Journal of Gemmology) specialising particularly in ivory, and he secured his Gemmology Diploma a year later in 1934.


Early Articles by Webster.

Robert Webster’s gemmological career went from strength to strength: in 1942 he became an assistant lecturer at Chelsea Polytechnic and, following WWII, he was invited by Basil Anderson to join the Testing Laboratory team in Hatton Garden, to tackle the new challenge of calibré synthetic corundum. In the first year alone they tested 105,000 stones!

In the 1940s the Gemmological Association established the Research Diploma, to encourage and recognise excellent postgraduate research by Fellows of the Association. Robert Webster is one of only six people to be awarded this coveted Diploma for his thesis on ivory and its various imitations. It made such an impact that renowned mineralogist Dr Herbert Smith added sixteen pages to his 1949 revision of Gemstones!

Collection of Editions of Webster's Compendium, with document from Annual Report of the testing lab for the London Chamber of Commerce

In 1937 Webster published his Gemmologists’ Pocket Compendium with “the intention to cover as concisely as possible all the information most useful to the practical gemmologist”. This captured the spirit of Gem-A’s ethos since 1908 of providing quality gemmological education for the benefit of the gems and jewellery industry, and was built on the very data recorded by Basil Anderson and C.J Payne, the compendium has been the ‘bible’ of professional and amateur gemmologists and retail jewellers.

Together with his 1941 Practical Gemmology and epic two-volumed Gems in 1962, Webster’s contribution to gemmological research has made him one of the most recognised voices in Gem-A history. His prolific work is still held in high esteem, to such an extent that when contributors were invited to revise Gems, gemmologists from Australia, Canada, Germany, Thailand, Vietnam, the UK and the USA answered the call.

Robert Webster © Gem-A.

On Webster’s death at the age of 77 in 1976, Anderson’s touching tribute to his friend’s memory serves as a testament to Webster’s impact on the gemmological world:

"So manifold and varied were the activities of Robert Webster in the field of gemmology that the gap left in our ranks by this death can never adequately be filled – not, at least, by any one person."

Robert Webster is remembered at Gem-A as one of our greatest gemmologists. Future gemmologists studying at Gem-A HQ in London are taught in the Webster Room, dedicated to his memory. To this day, Webster’s Gemmologists’ Compendium remains one of the most comprehensive guides for anyone studying gemmology. 

If you would like to join us in celebrating 110 years of gemmology education click here and register for the Gem-A Conference 2018.

If you are a Gem-A Member or Student you will have received an email to book member or student rates, if you haven't received it please contact membership@gem-a.com.

Cover Image: Photograph of Robert Webster from the Gem-A collection. Image Credit Gem-A


The Fascinating History of Antique Turquoise Jewellery

The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more


Birthstone Guide: Garnet For Those Born In January

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more


Getting Started with Quartz Inclusions

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more


Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more


Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more


Tanzanite: The Contemporary December Birthstone

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more


Birthstone Guide: Turquoise For Those Born In December

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more


Understanding the Cat's Eye Effect in Gemstones

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more


Jade and its Importance in China

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more


Highlights of Gem-A Conference 2019

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more


 

Additional Info

Read more...

Heritage Series: Sir James Walton, The Royal Surgeon

If you have had the chance to visit us here at Gem-A HQ, you may have had the opportunity to see the Sir James Walton Library, which is one of the largest collection of gemmological books in Europe and holds some of the greatest works in gemmological science, including Walton’s Practical Gemmology. But did you know that for the majority of his life Walton was a decorated medical professional and a surgeon to royalty?  

Sir James Walton was the President of the National Association of Goldsmiths 1953-55 and served as the Gemmological Association’s Chairman in 1955, following a long illustrious medical career. Walton was awarded the Fellowship of the Royal Colleges of Surgeons among his many qualifications, and was established both as an Officier de la Legion d’Honneur, and a Knight Commander of the Royal Victorian Order (K.C.V.O) which recognises personal service to a reigning monarch of the United Kingdom.


Sir James Walton

READ MORE: Heritage Series: The Trailblazing Efforts of Robert Webster

Born in 1881, James Walton was elected to the staff of the London Hospital in 1913, where he worked for 33 years. During the First World War, Walton was a Captain in the Royal Army Medical Corps (RAMC). Walton was stationed at the 2nd London General Hospital and served as a surgeon to the Empire Hospital specialising in diseases of the brain and spinal cord, and in WWII he was a Brigadier in the Army Medical Department.

In 1930, Walton was also appointed as surgeon to the Royal Household of King George V, and served through both his reign and those of his sons Edward VIII and George VI, until 1949. During his dedicated service he was official surgeon to Queen Mary from 1936-49, and it was through their shared enthusiasm for gemmology that Queen Mary honoured the Association by visiting the Gemmological Association’s Exhibition in 1951 at Goldsmiths’ Hall.

Queen Mary, Sir James Walton, and President Dr Herbert Smith
at the 1951 Gemmological Association Exhibition


Dedication in Walton's Practical Gemmology

READ MORE: Speaker in the Spotlight: Q&A with Dr Eloïse Gaillou

After an illustrious career, serving as President of the Association of Surgeons and the Medical Society of London respectively, Walton began his well-earned retirement in 1946, where he entered the fascinating world of gemmology.

While his investigation of gemstones was an enjoyable hobby, by Walton’s very nature this hobby developed into an intensive and specialised study. Despite not having the traditional background of most gemmologists, Walton mastered the subject of Crystallography and became a recognised authority on precious stones in the UK, accumulating in his book Practical Gemmology.


Dedications to B.W. Anderson and to Dr Herbert Smith by Sir James Walton in his 'Practical Gemmology'

Described by Robert Webster as ‘a valuable contribution to gemmology’ (JoG 1953 Vol.4.No.1), Walton’s book addressed an important gap: he had noticed that there was not a book aimed at the new or amateur gemmologist who did not have (or necessarily need) a scientific or geological background:

‘The majority of books are written in technical language and are interspersed with many mathematical proofs and equations from which they [non-specialists/hobbyists] shrink with aversion if not with horror.’

Walton aimed to gather ‘an account of the scientific principles upon which the subject of mineralogy is based’ but to ‘divest it as far as possible of all mathematical considerations, to present it in the simplest non-technical language…so that it may be of easy understanding even to those devoid of all scientific knowledge.’

READ MORE: Leading the World's First Gemstone Testing Laboratory: Gem-A's Basil Anderson

That being said, Walton’s book is of incredible scientific value, and included unpublished material by Basil Anderson and CJ Payne, who supported this important project that created an essential book for those who approached gemmology out of inquisitive enthusiasm. In 1947 Walton was also appointed the first curator of the Association’s collection of gemstones.  


Sir James Walton

Upon his death in 1955, a vast collection of Sir James Walton’s books and stones were generously bequeathed to the Association, and are now housed in the Sir James Walton library at Gem-A HQ London. So when you next visit us at Ely Place, please ask to visit our exquisite library and immerse yourself in a part of Gem-A history and Walton’s living legacy.


The Sir James Walton Library at Gem-A HQ London

If you would like to join us in celebrating 110 years of gemmology education click here and register for the Gem-A Conference 2018.
If you are a Gem-A Member or Student you will have received an email to book member or student rates, if you haven't received it please contact membership@gem-a.com.

Cover Image: Photograph of Sir James Walton from the Gem-A collection. All Image Credits: Gem-A.


The Fascinating History of Antique Turquoise Jewellery

The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more


Birthstone Guide: Garnet For Those Born In January

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more


Getting Started with Quartz Inclusions

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more


Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more


Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more


Tanzanite: The Contemporary December Birthstone

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more


Birthstone Guide: Turquoise For Those Born In December

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more


Understanding the Cat's Eye Effect in Gemstones

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more


Jade and its Importance in China

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more


Highlights of Gem-A Conference 2019

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more


 

Additional Info

Read more...

Heritage Series: Let's Bragg About It! Our Nobel Prize Winning Presidents

Did you know that two of Gem-A’s presidents were actually Nobel Prize Winners? Sir William Henry Bragg, the Association’s president 1937-42, and his son Sir Lawrence Bragg president 1954-72, were jointly awarded the Nobel Prize for Physics in 1915 for their research in X-ray Crystallography – an epic achievement that laid the foundation for future scientific breakthroughs and the basis of 26 other Nobel Prize winners and counting!

William Henry Bragg (WHB) had an exceptional mind, winning a Minor Scholarship to Trinity College, Cambridge, at the age of 17! The family considered this a bit too young, so a year later in 1881 WHB began the Mathematical Tripos at Trinity, and after graduating he began research at Cambridge’s Cavendish Laboratory to train in physics.

Sir William Henry Bragg. Image Credit: Gem-A.

In 1886, at the age of 23, he was appointed the Elder Professor of Mathematics and Experimental Physics at the University of Adelaide. Much of his time was taken with teaching commitments, leaving little room for research, but WHB maintained his interest in physics and kept up to speed with the latest developments by Prof. Wilhelm Röntgen at Würzburg, Germany, who had discovered an exciting new form of radiation, ‘so mysterious that he called it the X-ray’ (Hunter 2004: 6-8). At 41, WHB began to explore X-ray radiation, winning international recognition and was nominated to the Royal Society in 1907, and took the Cavendish Chair in Physics at Leeds, England in 1909.

Bragg’s first son, William Lawrence (WLB), was born in 1890 and later recalled that his father would tell his sons bedtime stories about the properties of atoms “We started with hydrogen and ran through a good part of the periodic table.” (Hunter 2004: 8; RI, MS WLB pp8-12).  Equally brilliant, WLB entered the University of Adelaide a year early at the age of 15 and achieved a First Class Hons in mathematics. When the family moved to England, WLB, like his father before him, entered Trinity College Cambridge, but switched from mathematics to physics.

Sir William Lawrence Bragg.
Image Courtesy of the Royal Institution of Great Britain.

WHB was aware of the recent Munich Experiment of 1912 where Max von Laue, Walter Friedrich and Paul Knipping targeted sphalerite crystals with X-ray beams, backed with a photographic plate to track the diffraction pattern. Today, gemmologists are quite familiar with diffraction patterns from X-ray spectroscopy, however, it is important to remember that at this time, scientists were still establishing the nature of X-rays, whether we were talking about waves or atom particles, and WHB was still yet to invent the first X-ray spectrometer:

"Nothing was certain then, X-rays were mysterious"
 Prof. André Authier, Université Piérre et Marie Curie.

It was the 22 year old WLB who fully realised the ramifications of Laue’s epic discovery that X-rays were diffracted by the crystal structure: he established the relationship between the wavelength of radiation, angles of incidence and diffraction, and the spacing of layers of atoms in a crystal structure. Knowing the first two, the third could be calculated. This became known as Bragg’s Law:

n λ = 2d sin θ

d being the distance between atoms by using geometry

This leap of genius was the key to measuring and understanding atomic structures, which could only be inferred up to that time. As he later said in his 1959 lecture to the Royal Institution:

"What is it, really, that makes a thing a crystal? It is it’s inside arrangement, it’s the fact that the molecules or atoms in it are an absolutely regular pattern, like soldiers on parade."


Crystallography in the Sir James Walton Library at Gem-A HQ. 

To facilitate this his father WHB designed the X-ray spectrometer:
"It contained a platform on which the crystal could be rotated with respect to the X-ray beam and an ionisation chamber that could be rotated around the crystal. The ionisation chamber contained a gas that was ionised by X-rays and an electrometer so that the amount of radiation detected could be qualified." (Hunter 2004: 35)

The impact of the Braggs’ research – and Bragg’s Law – cannot be overemphasised:

"it could be well argued that the scientific method of X-ray crystallography has been as great as those of quantum theory and relativity, and the impact on everyday life even greater." (Hunter 2004: xiii)

From this exciting realisation, father and son worked tirelessly over the Summers of 1913 and 1914, and in 1915 the younger Bragg received a telegram whilst on the Front in the First World War that he and his father had been awarded the Nobel Prize in Physics for their research in X-ray Crystallography.

This enshrined the Braggs into history.  Moreover, WLB was instrumental in supporting the British Expeditionary Force in France and Belgium in WWI by applying scientific sound ranging to locate enemy guns by sound.  In 1941 Bragg was a scientific liaison officer between Great Britain and Canada, and an advisor to the British Navy on antisubmarine work, and sat on the advisory council to the Minister of Supply.

Publications in the Sir James Walton Library at Gem-A HQ. 

Over the course of their careers both father and son were heavily involved with the scientific community at the Manchester Laboratory, the Cavendish Laboratory, and the Davy-Faraday Laboratory at the Royal Institution of Great Britain. Indeed, both Braggs were in turn appointed Resident Professor at the Royal Institution, and both served as Presidents of the Gemmological Association – a link that is revived again this year when we return to the Royal Institution for our Graduation, 80 years since William Henry Bragg presented awards to our graduates.

In his inaugural address WHB noted his honour at being our President:

Your Association has paid me a great honour in asking me to be your President…you must allow me to begin by address this evening by expressing my warm appreciation… I have of course no inner knowledge of your ancient, beautiful and wonderful craft and feel flattered that you have invited me, a physicist, whose concern in precious stones differs so much from that of the craftsman, to be associated with you in this honourable way… If, apart from their use as precious stones, crystals were regarded at one time as mere curiosities, the situation is entirely changed. We have learnt that the crystalline structure is one of the great orders of Nature, occurring everywhere and not merely in the rare specimen… I suppose that the jeweller looks to the diamond as the king of gems. To the physicist, the internal structure of the diamond is of extraordinary interest for its strong and beautiful simplicity and for the information which it gives as to the properties of the carbon atom. For the diamond consists of carbon alone, and the bonding facilities of the carbon atom are directly exhibited.  

Indeed, in keeping with the Basil Anderson's gemstone testing laboratory, WHB noted the importance of X-ray crystallography to the gemmologist, as it "gives you a means, if you need it, of deciding between the true and the false."

In 1954, Sir Lawrence Bragg was extended the same invitation to become our President. In his address, WLB appreciated the honour as both his father and their close friend, Sir Henry Miers, had both served the Association in this way. Just as we were created as a means to provide gemmological education to the wider jewellery industry, WLB firmly believed that scientists had a duty to share their knowledge:

"There is one sense, however, in which the pure scientist is, in my opinion, deeply wrong in withdrawing into his ivory castle.
He must pursue knowledge for its own sake,but at the same time it is his duty to see that
this knowledge is so digested, arranged, and simplified that it can become a possession of all those who desire to attain it."

It is fitting, then, that in 2018 we will be celebrating our Gemmology Diploma and Diamond Diploma Graduates at the Royal Institution on November 5, celebrating 110 years of creating gemmologists worldwide.

The Royal Institution of Great Britain. Image Credit: SB Gem-A.

If you would like to join us in celebrating 110 years of gemmology education click here and register for the Gem-A Conference 2018.

If you are a Gem-A Member or Student you will have received an email to book member or student rates, if you haven't received it please contact membership@gem-a.com.

Cover Image: Sir Lawrence Bragg, Courtesy of the Royal Institution of Great Britain. 


The Fascinating History of Antique Turquoise Jewellery

The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

Read more


Birthstone Guide: Garnet For Those Born In January

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more


Getting Started with Quartz Inclusions

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more


Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more


Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more


Tanzanite: The Contemporary December Birthstone

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more


Birthstone Guide: Turquoise For Those Born In December

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more


Understanding the Cat's Eye Effect in Gemstones

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more


Jade and its Importance in China

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more


Highlights of Gem-A Conference 2019

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more


 

Additional Info

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Delving into Diamonds: Gem-A President and Diamond Expert, Eric Bruton

There is one name in gemmological science that is synonymous with the study of Diamonds: BRUTON. Studying under the genius of Basil Anderson and Robert Webster, Eric Bruton had such an impact on the gemmological world that his work forms the basis of Gem-A’s Diamond Diploma to this day.

Born in London in 1915, Bruton started a career in publishing before joining the engineering branch of the RAF during World War II, where he was in charge of technical training and also served in India.

Eric Bruton ©Gem-A

On returning to the UK, Bruton was invited to edit four prominent publications: Industrial Diamond Review, Horological Journal, Goldsmiths’ Journal and – importantly for Gem-A – The Gemmologist, published by the National Association of Goldsmiths (NAG). Bruton immediately signed up for classes at Chelsea Polytechnic – then being led by Anderson and Webster – and began what would become a life-changing adventure into the world of gemmology.

READ MORE: Speaker in the Spotlight, Peter Lyckberg

Eric Bruton was awarded his Gemmology Diploma in 1950, and began teaching for the Association in 1967 – specialising in diamonds, running courses at St John Cass College London, and a similar course at Barcelona University – with examinations by The Gemmological Association of Great Britain. All of this was building up to Bruton’s breakthrough publication, his first practical handbook in 1970: Diamonds.

Until Diamonds, books on this subject were either highly technical or focused on one particular aspect of the industry. Recognising this problem, Bruton’s response was to cover all aspects of gem diamonds, spanning the history of diamond, mining and recovery, cutting methods, grading and valuation, and the identification of diamond and its simulants.

READ MORE: Investigating Fake Rough 

Throughout his research and his travels to various diamond mines across the world, Bruton realised that the various compartments of the diamond industry had little – or indeed no – knowledge of their counterparts. Most important of all, members of the public did not ‘appreciate that the possession of a diamond…has taken 4000 years of endeavour – blood, toil, sweat and tears – to produce the modern brilliant-cut diamond’ (viii).

Bruton was the ideal person to address this – with his editorial experience and gemmological expertise, he was in a rare and strong position to deliver.

Eric Bruton by David Langdon, 1971. Image Credit: Gem-A. 

Bruton’s Diamonds is a systematic study of all aspects of diamonds and forms the foundation of Gem-A’s Diamond Diploma. For many years, Bruton specialised in writing on all matters relating to gems, jewellery, and watches – and  even crime fiction! Bruton also founded the trade’s only newspaper of the time – Retail Jeweller – which, in competition with Watchmaker Jeweller & Silversmith - became the voice of the trade, and in 1994 was elected president of the Association.

READ MORE: Heritage Series, Let's Bragg About It! 


Today, Bruton’s contribution to the Gem-A is remembered with the Bruton Medal, a prize awarded to exceptional students with the best results in the Diamond Diploma examination, and the Bruton Room at Gem-A HQ in London, where future gemmologists study diamonds.

Interested in finding out more about gemmology? Sign-up to one of Gem-A's courses or workshops.

If you would like to subscribe to Gems&Jewellery and The Journal of Gemmology please visit Membership.

Cover Image: Diamond Crystal Trigons, photo by Pat Daly, with Bruton Medal. Image by Gem-A. 


The Fascinating History of Antique Turquoise Jewellery

The Fascinating History of Antique Turquoise Jewellery

In his third Gemstone Conversations column for Gems&Jewellery, Jewellery Historian and Valuer John Benjamin FGA DGA FIRV explores the fascinating history of turquoise and its use in jewellery design from the Shahs of Persia to the Art Deco design movement.

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Birthstone Guide: Garnet For Those Born In January

Birthstone Guide: Garnet For Those Born In January

If you're lucky enough to be born in January, vibrant garnet is your birthstone. A rainbow jewel of the gem world, garnet displays the greatest variety of colour of any mineral and is very often untreated, making it a rarity in the gem world. 

Read more


Getting Started with Quartz Inclusions

Getting Started with Quartz Inclusions

Do you know your calcite inclusions from your dumortierite, epidote, fluorite and rutile? Here, Charles Bexfield FGA DGA EG explores some incredible quartz inclusions and explains what to look for when shopping for quartz specimens.

Read more


Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Understanding Iridescence: Opals, Pearls, Moonstones and Fractured Stones

Iridescence has to be one of the most mesmerising and magical optical effects seen in gemstones. But have you ever wondered how it occurs? Gem-A's Collection Curator Barbara Kolator FGA DGA shines a light on this fascinating optical effect and tells us about the gems that are most likely to display it.

Read more


Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Hidden Treasures: Highlights of Gem-A's Gemstones and Minerals Collection

Gem-A Gemmology Tutor Pat Daly FGA DGA offers us a glimpse at some of the more unusual items in Gem-A's Gemstones and Minerals Collection.

Read more


Tanzanite: The Contemporary December Birthstone

Tanzanite: The Contemporary December Birthstone

Are you looking for the perfect festive gift for a December baby? Gem-A tutor Lily Faber FGA DGA EG considers tanzanite – one of three birthstones for December – and shares how this relatively new gemstone compares to its purple and blue-hued rivals.

Read more


Birthstone Guide: Turquoise For Those Born In December

Birthstone Guide: Turquoise For Those Born In December

Beautiful blue turquoise is one of three birthstones for the month of December (in addition to zircon and tanzanite). It is enriched with real cultural significance that can be traced back thousands of years. Here, we explore the blue shades of turquoise and explain what makes this gemstone so special...

Read more


Understanding the Cat's Eye Effect in Gemstones

Understanding the Cat's Eye Effect in Gemstones

Chatoyancy is the gemmological name given to the curious optical effect in which a band of light is reflected in cabochon-cut gemstones, creating an appearance similar to light bouncing off a cat's eye. Gem-A's Collection Curator, Barbara Kolator FGA DGA explains chatoyancy and highlights some of the many gems in which it can occur.

Read more


Jade and its Importance in China

Jade and its Importance in China

Jade has long been revered by gem lovers internationally, but nowhere more so than in China. But what is it that makes this gemstone so special? Gem-A's Assistant Gemmology Tutor Dr Juliette Hibou FGA gives us an overview of jade, how to identify it and its significance in Chinese culture.

Read more


Highlights of Gem-A Conference 2019

Highlights of Gem-A Conference 2019

The Gem-A Conference is always the highlight of our gemmological calendar! If you didn’t manage to make it, we’ve put together a few of the highlights from this year’s event to fill you in on what you missed, and whet your appetite for Gem-A Conference 2020!

Read more


 

Additional Info

Read more...

誕生石ガイド:1月生まれのあなたに捧げるガーネット

 

幸運なことに1月に生まれた方は、美しく、明るく、鮮やかなガーネットが誕生石です。虹色 の宝石、ガーネットは実に様々な色をもつ鉱物で、業界では処理を行わないごくわずかな宝石 の一つに数えられます。

ガーネットは様々な彩度、種類、色相がある絵具のパレットのようであり、豊かな歴史と伝説 があることでも知られています。ヴィクトリア時代の王族、古代エジプト時代の歴代王、古代 ローマ人をはじめ、多くの時代で好まれた宝石です。


きれいなホーステール・インクルージョンが見られるデマントイド・ガーネット。写真:Pat Daly

ガーネットの色

ガーネットは赤色部に強いスペクトルもち、ざくろの実を思い起こさせるような赤褐色を帯び たオレンジ、濃いバイオレット、ロイヤル・レッドの色合いを示します。「ガーネット (garnet)」は14世紀中期に使用されていた濃い赤色を意味する英語の「gernet」にちなみ、 さらにはラテン語の「ざくろの実(種)」を意味する「グラタナス(granatum)」に由来する 名前です。これはガーネットの結晶がざくろの種や濃い赤色に似ているためです。ガーネット とは、赤色のパイロープ・ガーネットから趣のある緑色をしたツァボライト・ガーネットまで 、鉱物のグループを指す用語です。

ガーネットの色が様々であるのは、マンガン、鉄、クロムなどの微量金属によるものです。ガ ーネットの変種で異なる化学組成は、硬度に6.5-7.5の範囲をもたらす原因となります。

偏光器下でのガーネットとペリドタイト。写真:Pat Daly

左: フェザー・インクルージョンを伴うスペサルティン・ガーネット。右:結晶インクルージ ョンを伴うヘソナイト・ガーネット。写真:Pat Daly

ガーネットの種類

ガーネットには、同じ結晶構造にもかかわらず、若干異なる化学組成をもつ5つの主な変種があ ります。

  • アルマンディン:紫色から帯橙赤色
  • パイロープ:紫色から帯橙赤色
  • スペサルティン:橙色から黄色
  • アンドラダイト:黄色から帯黄緑色
  • グロッシュラー:無色から黄色、帯橙赤色、鮮やかな緑色(稀少)

 

ガーネットはどこで採れるのか?

ガーネットはオーストラリア、インド、チェコ共和国、ミャンマー、ブラジル、スリランカな ど世界中の多くの国々で見つかります。19世紀にはジュエラーのピーター・カール・ファベル ジェ(Peter Carl Fabergé)が製作した多くの作品にガーネットが用いられ、ロシアの王族に愛 されました。ボヘミアやロシアは19世紀の最初のガーネットの産地として記録されていますが 、現在では、タンザニアやナミビアでガーネットが豊富に採取されます。

デマントイド・ガーネットのホーステール・インクルージョンを拡大した写真。写真:Pat Daly

ガーネットの歴史と古代の伝説

ガーネットには長い間語り継がれてきた歴史と多くの言い伝えがあります。「誠実の宝石」と して知られるガーネットは健康、繁栄、平和の力をもち、この石を身に着ける者は善い行いを して報われると言い伝えられてきました。鮮やかで強い印象をもつガーネットは、活気に満ち た1月に生まれの方に相応しい石であると考えられています。そして、ガーネットを着ける 人は新たな目標をもち、希望と幸福を感じながら新年を迎えることができるとされています 。

また、戦いに臨む人々は勝利と身の安全を祈る護符としてこの宝石を使いました。多くの戦士 たちが病気や貧窮を防ぐために身に着け、戦いで負った傷に石を当て、治癒を促すものとして 使用しました。さらに歴史を遡ると、エジプトではガーネットを生命の象徴としてジュエリー や彫刻に象嵌しました。古代ローマ人は好んでガーネットをシグネット・リング(印章付きの 指輪)に用いました。これは石に沈み彫りを施し(インタリオ)、重要な文書に封印をするも のです。健康にも効果があるとされたため、歴史を通じて聖職者や貴族階級の間で珍重され続 けました。


マリ産のガーネット。写真:Pat Daly

今日、ガーネットはリング、ペンダント、ティアラなど様々なジュエリーに使用されています 。その色と透明度が、作品を価値ある素晴らしいものに仕上げているのです。

ガーネットが使われた大変有名なジュエリーの例として、ヴィクトリア時代に製作されたスミ ソニアン・パイロープの髪飾り(the Smithsonian Pyrope Hair Comb)が挙げられます。頂上の 中央石を取り囲み、ティアラの形をした髪飾りを装飾するパイロープ・ガーネットは、ボヘミ アの鉱山(現在のチェコ共和国の一部)で採取されたものです。このローズ・カットを施した ガーネットはメッキをした金属またはイエロー・ゴールドにセットされました。この作品が流 行したヴィクトリア時代には人気のあるスタイルでした。

今年の成功を祈る護符として、また1月生まれの方への贈り物として、個性的なガーネットのフ ァイアと煌めきは、強く感情を揺さぶり、時を超えた美しさをもつことでしょう。

 針状のルチル・インクルージョンを伴うマラヤ・ガーネット。写真:Pat Daly

表紙:結晶インクルージョンを伴うアルマンディン・ガーネット。写真:Pat Daly ©Gem-A

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婚約指輪に使われたダイヤモンドの歴史

 

ジャック・オグデンFGAが、婚約指輪に使われていたダイヤモンドの歴史について見ていきます 。この習慣がどれほど古いものなのか、少し驚くかもしれません...

ここで皆さんに質問があります。婚約指輪に関する次の文章を読んでください。「婚約指輪に は、250から2000ドルと価格に幅があるが、現代ファッションにおいてはダイヤモンドのソリテ ール(一石のダイヤモンドを留めたリング)と定める」。これがいつ書かれたものであると思 いますか?第二次世界大戦の前でしょうか、後でしょうか?

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ロンドン塔の収蔵品「クラウン・ジュエル」

 

アンドリュー・フェローズ FGA DGAが、世界で最も有名な宝石コレクションである「クラウン・ジュエル」にまつわる神話や伝説を見ていきます.

有名なクラウン・ジュエルCrown Jewels が収められているロンドン塔の基礎は、征服王ウィリアムによって1066年に築かれました。そして、代々の君主たちによって改造や修復が重ねられ、13世紀後半までには今日見られる大体のレイアウトが確立しました。ヨーロッパで唯一現存するクラウン・ジュエルは141以上の宝物で構成され、何百年もの間ロンドン塔の中で安全に保存されてきました。これらは毎年、多くの観光客を惹きつけています

このコレクションには、単に宝物の美しさを堪能する価値があるだけでなく、宝石類の背後にある魅惑的な物語と歴史について学ぶ価値もあります。

帝国王冠(インペリアル・ステート・クラウン)

帝国王冠(インペリアル・ステート・クラウン)―コレクションにおける最も有名な王位の象徴― は、即位式終了後に君主が頭上に戴くもので、議会の開会の際にも使われます。王冠には、このような重要な行事に際して、王冠自体と同じくらい凝った専用の儀式用馬車が用意されています。王冠は実に3.17kgもの重量があり、短い間のみかぶることができます。

ジョージ4世が1821年に戴冠した際、王冠の重さが理由で歯痛になったという逸話があります!王冠にはロイヤル・コレクションにおいて重要な宝石がいくつか使われており、その多くには非常に面白い物語があります。

黒太子のルビー

多くのジェモロジストがよく知っている物語の一つとして、黒太子のルビーが挙げられます。これは、最も美しい宝石であると同時に最も不吉な石といわれています。そればかりか、完全に誤った名がつけられています。ルビーと呼ばれていますが、実際は非常に大きな宝石品質のレッド・スピネルです。この宝石は、デューク・オブ・コーンウォール、プリンス・オブ・アキテーヌと呼ばれ、「黒太子」とも称される14世紀のプリンス・オブ・ウェールズであったエドワード皇太子(エドワード・オブ・ウッドストック)に贈られました。

The Imperial State Crown. Copyright Cyril Davenport. Tower of London
帝国王冠(インペリアル・ステート・クラウン). Copyright Cyril Davenport

王冠の前部のカリナンIIより上にあるクロスパティー(末広十字)についているこのスピネルには、黒い、血の歴史があります。14世紀に書かれた最初の記録によると、ムーア人の皇太子であったアブー・サイードがこの石を所有し、ペドロ残酷王が征服していた軍隊に引き渡そうとしますが、彼は休戦旗の下で待ち伏せされ、奪われたこの大きなスピネルで処刑されました。これがまさに血の軌跡の始まりです。その後、ペドロは軍事援助のための頭金としてこの石をエドワード皇太子に差し出しました。支払いの残りは宝物と宝石から成ると思われていましたが、決して支払われることはありませんでした。そして、結局、ペドロは彼の異母兄弟に待ち伏せられて刺し殺されました。

後にこの石は、1415年のアジャンクールの戦いで、ヘンリー5世のヘルメット(兜)につけられ、言い伝えによると石が彼の命を救ったとされています。斧で彼の頭が強打されたときそのヘルメットは破壊されたものの、彼を死に至らしめることはありませんでした。「ルビー」は粉砕されたヘルメットから取り出され、ヘンリー5世が亡くなるまで手元に置かれました。残念なことに、リチャード3世に関しては同じことは起きませんでした。彼もまた1485年のボズワース・フィールドの戦いのとき、「ルビー」をヘルメットにつけていました。おそらく、彼は石が身を守ってくれる、運をもたらすと思っていました。しかし、悲しいことに、彼は戦場で死んでしまいます。この同じ「ルビー」は後にチャールズ1世によって売却されるまで、ヘンリー6世とエドワード4世の王冠、ヘンリー8世(彼は石をを襟に着けていた)に使われました。そしてこの石は王室に戻りチャールズ2世の王冠に用いられ、その後ジョージ4世の即位式で使われました

聖エドワードのサファイア

また、帝国王冠の上部の十字架には、サファイアがセットされています。伝説によれば、このサファイアは、かつて証聖王エドワード(信仰のあつい英国王)の即位の指輪(コロネーション・リング)につけられていました。ある夜、エドワードがウェストミンスター寺院の前を通ると、一人の乞食に遭遇しました。彼は持っていたすべてのお金をすでに寄付してしまっていたので、深く考えずにその乞食にサファイアのついた指輪を与えました。

数年後、2人のイングランド人が聖地巡礼中、嵐に襲われました。その時1人の老人が彼らに近づいてきました。そして、2人の男がイングランド人であること、エドワードが今も国王であることを聞き、その老人は彼らに嵐の避難所を提供しました。翌朝、彼らが出発する際、老人は、自分が福音記者ヨハネであることを明かし、数年前にエドワード国王が指輪をくれたことを話しました。老人は親切のお礼に6か月後に天国で会うでしょうというメッセージとともに指輪を国王に返してほしいと彼らに託しました。2人の男がイングランドに帰国すると、エドワード国王に指輪とメッセージを渡しました。そして、国王は直ちに自らの死に備えました。国王は6ヵ月後に亡くなり、指輪をはめて埋葬されました。不思議なことに、事実、墓が12世紀に再び開けられたとき、その指輪は完全に保存された遺体の上で見つかりました。

Tower of London at night. Copyright Kjetil Bjørnsrud. Tower of London
夜のロンドン塔. Copyright Kjetil Bjørnsrud

これらの物語の一部は単に伝説であって、本当かもしれませんし、そうではないかもしれません。しかし事実として、クラウン・ジュエルの中で最も有名で世界で一番大きなダイヤモンドは、コー・イ・ヌールとカリナンであると言えるでしょう。

カリナン・ダイヤモンド

カリナンは、1905年1月26日の午後に南アフリカのプレミア鉱山で、鉱山本部長であったキャプテン・フレデリック・ウェルズによって発見されました。それは3106ctの重さ、3 7/8×2 1/4×2 5/8インチで、その日までに発見された他のどのダイヤモンドよりも2倍以上の大きさであったため、当初、彼はこの石がダイヤモンドであることに疑いをもちました。その後、石はトランスバール政府に£150,000で売却されました。そして、2年後には未カットの状態でエドワード7世の66回目の誕生日に贈られました。その規模や価値はわからなかったものの、石のカットは、大きな石をカットする経験のあるアムステルダムのI. J.アッシャー・アンド・カンパニーに依頼され、3ヵ月検討した後、ようやくカリナンはカットされることになりました。

当時、ダイヤモンドを分割する唯一の方法は劈開を利用することでした。―ダイヤモンドの弱い方向に沿って割れるように正確な方向を「打つ」方法ですが、粉砕することを避けるために、慎重に行わなければなりませんでした。そして石を慎重に劈開させた結果、9個の大きな「かけら」と96個の破片になりました。全てのカット工程が終わった後に残った重量は合計1063ctでした。

カリナンⅠ~カリナンⅨと名付けられた9個の大きな石はすべて、ロイヤル・コレクションに属しています。大きい石は、他のジュエリーにも使用できるようにセッティングが作られます。別名「アフリカの星」と呼ばれるカリナンⅠは王笏に用いられ、503ct以上の重さがあります。この石は世界最大の無色のペア・シェイプ・ダイヤモンドです。カリナン II(「アフリカの小さい星」)は、世界最大のクッション・シェイプ・ダイヤモンドで、317ctの重さがあり、帝国王冠の正面にセットされています。この石にもセッティングには2つのプラチナの輪がついており、取り外しが可能です。そしてブローチやペンダントとして単独で着けられ、またカリナン Iと共に着用することもできます。

コー・イ・ヌール・ダイヤモンド

2番目に注目に値するダイヤモンドは、皇太后の王冠にあります。これはコー・イ・ヌールと呼ばれており、「光の山」という意味をもちます。この印象的なダイヤモンドの現在の重量は105.6ctで、もともと186ctあったこの石は、1852年にヴィクトリア女王のためにリカットされました。

この石は、身に着ける女性に幸運をもたらすという伝説があります。しかし、男性には不幸がふりかかります!1739年にペルシャのナーディル・シャーがムガルを征服しましたが、統治者がもつとされるこの珍しい伝説のダイヤモンドを見つけることができませんでした。宮廷の1人が彼にこの石の在り処を話すと、シャーは祝賀会を開き、永遠の友好のしるしとして征服された指導者たちとターバンを交換することを申し出ました。なぜなら、これがコー・イ・ヌールの隠されている場所であったからです。

ダイヤモンドはその後、数十年の間しばしば持ち主が変わりました。1850年までに、コー・イ・ヌールはイングランドへ伝わり、ヴィクトリア女王へわたり、そして現在に至ります。

クラウン・ジュエルは素晴らしいイギリスの歴史がある一方で、伝説に包まれた装飾品以上の存在です。ここには多くの物語と歴史があり、訪れる人々がそれを発見するのを待っています。宝石学的、歴史的な視点でこの宝物を鑑賞するのも良いですし、決して買うことができない宝石を見るのも感動的です。ロンドンで有意義な一日を過ごす方法として、クラウン・ジュエルはお勧めです■ 

この記事はGem-Aの機関誌Gems&Jewellery Sept/Oct 2016 / Volume 25 / No. 5 pp. 14-15から引用したものです。

表紙はカリナン・ダイヤモンドの原石から分割されたカット前の9つの石を大きいものから順に並べたもの。


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