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Top 5 Most Recognisable Gemstone Inclusions for Gemmologists


Gemstone inclusions are a fascinating area of study for gemmologists, but they can also be helpful in determining the identity of a stone and, in some cases, may be indicative of its origin. You may instantly recognise some inclusions if you have completed the Gem-A Gemmology Foundation or Gem-A Gemmology Diploma. Here, Tutor Pat Daly explores some of the most instantly recognisable internal features of gemstones.  

The term inclusion refers to any feature seen in a gemstone. It includes solids, liquids and gases, colour distribution, fractures and cleavages and structures related to the formation of the material. 

Gemstones may be crystals, polycrystalline masses, rocks, materials produced by the activities of living organisms, or by the collision of extra-terrestrial materials with Earth. The internal features of each of these types depend partly on how they were formed and may give clues to the processes involved. Inclusions in diamonds, for example, provide insights into Earth's mantle and the deeper parts of the crust and supply evidence of the rocks in which they formed and the conditions in which they grew. This information is welcome because these areas of our planet are inaccessible, and diamond is one of the few materials which encapsulate and protect it from alteration.


Gemstone Inclusions as Identifying Features 

Inclusions can help gemmologists to decide the identity and source of a gemstone and whether it has been treated in any way. Artificial materials such as synthetic stones are recognised chiefly by their inclusions. Often, it is not a simple matter to make these decisions, and other methods, which may not be accessible to gemmologists outside laboratories, may be needed to confirm them.

Fracture filled diamond from the Gem-A Archives.


One way of classifying inclusions is by their time of formation relative to their host. Some formed before the growth of the stone in which they are found, others at the same time and some after the host gemstone had stopped growing. The first two groups are beneficial for recognising gem species and their sources and whether they are natural or artificial materials. Inclusions which postdate or have been changed after the growth of their host can be used to recognise treatments, such as heat treatment, fracture filling and artificial colouration. 


Crystal and Fluid Gemstone Inclusions 

They may also be divided into crystals and fluid inclusions. Crystals can form either before or at the same time as the stone in which they are seen but fluid inclusions, excluding air-filled fractures and cleavages, form during growth. Many are irregularly shaped, but some have the shapes of crystals and are called negative crystals. These may sound unlikely, but they are common. 


Negative crystal inclusions in corundum photographed by Pat Daly.


Fluid inclusions may contain liquid, gas or both and may also enclose crystals. Two-phase inclusions enclose two of them, and three-phase inclusions all three. The term monophase may be used for those containing only liquid or gas, but it is used less often. 

Fluid inclusions may be arranged in feathers. Feathers are planar or curved planar features in gemstones and artificial materials. Those composed of fluid inclusions are thought to form when stones break during growth, and fluids which contain their chemical ingredients are drawn into the cracks, partially repairing them.


Gemstone Inclusions and Visual Appearance

Some inclusions add to the visual appeal of gemstones. For example, abundant, oriented needle-like crystals are responsible for star and cat's-eye effects in some cabochon-cut stones. Aventurescence, a spangled or sparkling effect, depends on parallel platy crystals which act as tiny mirrors in some quartz gems and sunstone feldspars.


Cat’s eye chrysoberyl photographed by Pat Daly.


Crystal inclusions are sometimes valued in their own right. Quartz crystals, for example, form in many geological environments and may enclose any mineral which can coexist with it (peridot, and some others, cannot). This means that interesting collections can be made of many minerals, some of which are colourful and well-formed. Minerals which are not durable enough to be suitable for use as gemstones can form desirable varieties when they are enclosed and protected by quartz. Examples include chrysocolla, a sky-blue mineral which usually discolours when exposed to air but retains its beautiful appearance when included in quartz, and rutile, golden needles that are easily broken except when they occur as inclusions. 


The Top 5 Most Recognisable Gemstone Inclusions 

Of all the inclusions found in gemstones, a few may be mentioned as being particularly well-known and representative of the different types. Many inclusions might compete for the list, but the following five have been chosen.


Tiger Stripe Inclusions 

Tiger stripe, also known as zebra stripe, is a type of feather found in amethyst. It is distinctive, unsurprisingly, because it is marked by wavy stripes. The inclusion is related to twinning in the crystal, is sometimes iridescent and may consist of three distinct sectors reflecting the mineral's trigonal symmetry. 

Tiger stripe inclusions in amethyst photographed by Pat Daly.


Tiger stripe in a purple stone may be regarded as proof that it is amethyst. It may also be seen in some citrines produced by heat-treating amethyst. It is taken as evidence of natural origin, though there are reports that it may be induced in synthetic stones.


Horsetail Inclusions

When complete, horsetail inclusions in demantoid garnet consist of a dark crystal of chromite (chrome and iron oxide) surrounded by a spray of radiating, golden-coloured fibres, which may be asbestiform serpentine or channels in the stone. Demantoid has a RI above the limit of the standard refractometer, so these inclusions, or some part of them, afford welcome confirmation of identity. The best-known source for demantoid is Russia, but there are other sources. Horsetail inclusions occur in stones from some of them, not from others.


Horsetail inclusion in demantoid garnet photographed by Pat Daly.


Animals and Plants Preserved in Amber

Amber is a gem material famous for the animals and plant remains it preserves as fossils. These are of general interest to gemmologists and jewellers, but they represent a treasure trove to palaeontologists trying to understand ancient environments. Fossils include flies, which may be very well preserved, showing details of the wings and limbs of the animals. Spiders, mites and other small creatures are relatively common, and rare vertebrate fossils are found. 


A fly trapped in amber photographed by Pat Daly.


However, any buyer of an expensive piece containing one is well-advised to obtain an independent opinion of its authenticity. The most exotic remains are those thought to have belonged to small dinosaurs. 


Three-Phase Inclusions in Colombian Emerald

Gemmology students soon become acquainted with the three-phase inclusions found in Colombian emeralds. These consist of a bubble in brine, accompanied by a square or oblong-looking crystal of salt enclosed in a spiky cavity. The crystals are cubes but often appear two-dimensional because the cavities are so thin. Three-phase inclusions are not confined to emeralds from Colombia or to emeralds; they have been seen in stones of other gem species and even, on occasion, in synthetic emeralds. Nonetheless, experienced laboratory gemmologists can use these inclusions to identify emeralds as natural and, by close study, assist them in stating the likely source of a stone.


Three phase inclusions in emerald photographed by Pat Daly.


Colour Zoning in Gemstones 

Colour zoning may seem commonplace in gemstones, but it can reveal much about their identity and history. Straight colour zoning is a well-known feature of natural blue sapphires and the citrine variety of quartz, for example. It is more helpful when it is appreciated that, although possible in any species, it is uncommon in yellow and blue stones other than these. 

Main image: tiger stripe in amethyst photographed by Pat Daly. 

Angular colour zoning in sapphire photographed by Pat Daly.


Kyanite and some rare blue euclase display it, but they are exceptions which are easily identified by other means. Flux-grown synthetic sapphires show straight colour zoning, so the feature does not guarantee that a stone is natural, though most synthetic sapphires are made by the Verneuil process and display curved colour zoning. The pattern of colour concentration may also reveal the colour treatment of sapphires and other gems. 

Inclusions in gemstones are useful because they provide gemmologists with ways in which gemstones may be identified, and artificial stones and treatments may be recognised. Those who study gemmology also come to see that inclusions are fascinating, often beautiful features which add greatly to the pleasures of studying the materials with which they deal in their everyday work.


British Gems: What Gemstones Can Be Found in Great Britain?


As the Gemmological Association of Great Britain, we have a special interest in gemstones that emerge from our home nations of England, Scotland and Wales. Here, Gem-A Tutor Pat Daly FGA DGA takes a closer look at the metals, gems and ornamental materials found within the borders of Great Britain, including quartz, topaz, jasper, agates and blue john. 

Great Britain, as opposed to the UK or the British Isles, consists of England, Scotland and Wales, together with several islands, including the Isle of Wight and the Hebrides. Within this area, a wide variety of metals, gem and ornamental materials are found, although the quantities in which they are recovered are small. Most occurrences are in ancient mountain belts, which extend from Scotland through the Lake District to Wales, and across Cornwall and Devon.

Can Important Gem Species Be Found in Great Britain?

Of the more important gem species, there are teasing reports that a few diamonds have been found in the Northwest Highlands and the Southern Uplands of Scotland, and that intrusions capable of bringing them to the surface exist in Scotland and in Devon. 

Sapphires, too small to be polished, have long been known from Mull and Ardnamurchan, in Scotland, but gem quality stones were only found in 1984 in an igneous intrusion in the Isle of Lewis. The largest faceted stone from here weighed about 10 carats. The exposure is small, only a few square yards in area, and was found when a farm track was cut through it. This locality is close to a road in a (thinly) inhabited area and illustrates the important point that over much of Britain rocks are concealed beneath bog, forest, moor or farmland, and a great deal remains to be discovered. 

Other important points are that all of Britain is owned, mining rights have been claimed over most of it or, like the source of sapphires, localities are included in sites of special scientific interest and must not be disturbed. 

Smoky quartz, blue topaz and aquamarine have been found in the Cairngorm Mountains. They aroused a great deal of interest in the 19th century, were set in jewellery of distinctive Scottish styles and are included in royal collections. The largest surviving topaz crystal, which is now in the Natural History Museum in London, weighs about 700 grams. 

Gem quality red garnets are found on the north side of the Firth of Forth, small gem quality tourmalines are found in Aberdeenshire and have been reported from Cornwall and small gem zircons have been recovered from several Scottish localities.

British Jasper and Agate Gemstones 

Jasper and agates are found in fields and on beaches in many parts of Britain and are so well known from Scotland that they have been called Scotch pebbles. They occur in what were once were once bubbles in volcanic rocks and are found most often in and around the Midland Valley. The Scottish Islands also produce these stones and there is a locality in Rum called Bloodstone Hill because of the occurrence of that stone. Beaches in Northern England, Cornwall and Wales also yield agates, and they have been found inland in Somerset. 

Jasper from the Gem-A Gemstones & Minerals Collection.


Pearls from British Rivers 

Pearls were once fished from British rivers, most recently from some Scottish ones, and it is thought that control of a source of pearls was one of the reasons for Julius Caesar’s invasion of England. Pearl mussels are long-lived and require clean water and lack of disturbance to prosper. They are now rare; disturbance of any kind is illegal and only those which were recovered prior to 1998 may be sold legally. 

Decorative Materials Mined in Great Britain 

Other decorative materials from north of the border include prehnite, various marbles containing serpentine, such as those from Iona and Skye, and granites, which have been used in Scottish-themed jewellery.

Views of Skye in Scotland. Image courtesy of Reuben Teo, Unsplash. 


England has produced gem materials as well, though they are not among those that many people associate with the word. Jet, a black, opaque variety of fossilized wood from around Whitby in Yorkshire, has been used for centuries, and was very fashionable during the later 19th century. It is fashioned and set in jewellery today although smaller amounts are available to craftspeople. 

Amber, another fossil material produced by trees, may be found on the coast from Suffolk to Lincolnshire. It was thought that it had been transported from the Baltic, but recent studies suggest sources beneath the North Sea. Amber is also found on the Isle of Wight, but it is of scientific rather than gemmological interest. The oldest amber, dating back to about 300 million years, has been found in coal seams in Yorkshire. This material too is of scientific rather than commercial interest.


Gypsum satin spar photographed by Pat Daly.


Cumbria was a source for the grey, metallic-looking gem material hematite, an important ore of iron, though mining has now ceased. Gypsum has been mined in the midlands and elsewhere for centuries. From about the 14th to the 16th centuries, it gave rise to an industry producing carved panels, mostly with religious themes, which decorated churches and private dwellings in England and abroad. 

The fibrous variety of gypsum, called satin spar, could also be used for decorative purposes. Another variety of satin spar, cut from veins of fibrous calcite, a by-product of Cumbrian metal mining, was popular in the late 18th and early 19th centuries.



Hematite rough photographed by Pat Daly.


Blue John from Great Britain 

Blue john is a variety of massive fluorite which is unique to Great Britain. It has been mined in Castleton, in Derbyshire, at least since the mid-18th century and became very popular at about that time. Many examples of ornaments made from this blue and yellowish-banded stone may be seen in museums and in stately homes which are open to the public. Small amounts are mined today and are used mostly in jewellery. Fluorite from other localities, such as Weardale in County Durham, has been faceted for collectors, though it is rather soft and fragile for normal wear.


Blue john photographed by Pat Daly.


Decorative Limestones from Great Britain 

The midlands and the north of England also produced decorative limestones. One of them, a black rock from Derbyshire, was used as a base material for inlay, in which coloured stones were set in the plain material to create naturalistic patterns. This work was carried on as a local industry during the 19th century, producing decorative household items and pieces suitable for jewellery.

Limestone which incorporates algal growths forms patterns which resemble trees and hedgerows. This “landscape marble” is still recovered near Bristol. Well preserved fossil trilobites in limestones from Dudley, in Worcestershire, were sometimes set in jewellery, an example of which is in the collection of the Natural History Museum, and small ammonites from Lyme Regis, in Dorset, have been used to make castings for jewellery.

Quartz Gemstones from Devon and Cornwall 

Cornwall and Devon, in southwest England, have produced several gem materials, notably quartz gems such as amethyst, rhodonite and rather porous turquoise as mining by-products. A small industry developed from the carving of serpentine which can be found on the beaches of the Lizard Peninsula, and these may be found in shops in the two counties. 

Rhodonite from the Gem-A Archives.


British Gold and Silver Mining 

In addition to gemstones, gold and silver may be found to set them in. Most gold has been found in North and mid Wales, but Cornwall and Devon have produced it, and there was a gold rush in Helmsdale, Sutherland in 1869, when a miner, returned from Australia, recovered a quantity of gold from the rivers and burns there. Gold has also been found in the Southern Uplands and elsewhere, and professional exploration and evaluation of Scottish sources is now in progress. Silver has been mined in the west and southwest of England, Derbyshire and the Pennines, mostly as a by-product of lead mining, in Wales and in Scotland, and was once an important source of precious metal for coinage. 

Great Britain is not a major producer of gem materials, but it hosts a wide variety of them and some of them are to be found around our coasts, where agates, jet and amber may occur. It is worth looking among the stones of most pebble beaches in the hope of finding something of gemmological interest.



Understanding Precious Black Opal and its Properties


We often hear about black opal, but what causes this dark body colour and what contributes to its market value? Here, we take a deep dive into precious black opal and discover where it is mined, how it can be treated and what simulants and synthetics are worth looking out for. 

What are opals? 

Opals are made of silica SiO2 with up to 20% water (usually closer to 4-10%). They do not possess a crystalline structure; they are amorphous, with no directional optical properties. 

Opals form when a hot silica rich solution permeates veins and voids in the ground. They are typically found in volcanic or sedimentary environments. Over a long period, the solution precipitates at low temperatures allowing the gradual formation of layers of minute silica spheres ranging from about 150 to 300nm. If an opal is made up of areas of regularly stacked, three-dimensional groups of spheres of equal size, then a combination of optical phenomena causes patches of spectral colour firing from the opal as it is tilted in the light.

What makes an opal precious?

Opals are defined as precious opals (as opposed to common opals) when they display these flashes of vibrant rainbow colours. This optical phenomenon, unique to opal, is called ‘play-of-colour’. The best precious opals display all the spectral colours from red to violet. This is a feature that led the Roman naturalist Pliny the Elder (Ist c. AD) to describe precious opals in his Natural History as if they were all the gemstones rolled into one:

“This most beautiful of gems combines the fire of the ruby, the brilliant purple of amethyst, and the sea-green of emerald; all shining together in glorious and incredible union.”

The beauty and mystery of this optical phenomenon made opals one of the most precious gems in Antiquity and the Middle Ages. They are sometimes referred to as the ‘queens of gemstones’. The fiery and iridescent qualities of opal have inspired poets like William Shakespeare who, in Twelfth night, crafted a metaphor between the fleeting colours of opal – and taffeta- and the changing mind of Duke Orsino: 

“Now, the melancholy god protect thee, and the tailor make thy doublet of changeable taffeta, for thy mind is a very opal.”

How is play-of-colour created? 

Play-of-colour is caused by a combination of two optical effects: diffraction and interference. The minute silica spheres, if regularly stacked and if arranged in groups of equal size, create minute gaps that are of the same size as the spheres. These gaps between the spheres act as small, regular apertures which cause white light to diffract as it passes through them. As light is diffracted, all the wavelengths are spread and become visible as spectral colours. The diffracted wavelengths then interfere to boost certain colours and cancel others.

A 7.07-carat fine gem-quality black opal. Photo courtesy of Cody Opal.


The colours visible in the play-of-colour depends on the sizes of the spheres/gaps. Some precious opals produce a full range of spectral colours. Areas made of smaller spheres (about 150nm), show violet to green or violet to blue flashes. When the spheres are bigger (about 350nm) red or orange patches of colour are produced. Depending on which angle the light hits the opal, it is diffracted differently due to the complexity of the structure, creating this fleeting, almost mystical, effect. 

The ‘play of colour’ shows off much better on a dark background. As a result, black precious opals are deemed more beautiful and are more sought after. 

Why are opals black?

Black opal owes its dark coloration to fine particles in its composition. The nature of these trace elements can vary. Carbon and iron sulfides (pyrite and chalcopyrite) formed microbially during the solidification process are mainly considered as being responsible for the dark colour. The body colour of these opals is dark, ranging from pure black to dark grey or chocolate brown, depending on the environment in which they formed. 

Black opal ring photographed by Pat Daly at Gem-A.


Where are precious black opals found?

Precious black opals are scarce. There are only few localities where black opals are found. The main one today is around Lightning Ridge in New South Wales, Australia where the first black opal is thought to have been found in 1877. Mintabie is known for a more greyish-black material. Most of the black opals on the market come from Australia

Ethiopian opals are a more recent find. The most important discovery was made in 2008 near the town of Wegel Tena in the Wollo region. Known as the ‘welo opals’, some show a dark brown body colour with a vivid play-of-colour. These Ethiopian opals tend to have a higher water content in their composition and are therefore not always suitable for use in jewellery. Some are hydrophane (absorbent). Since 2013, further North in the Wollo region, at the Stayish mine, grey to deep black precious opals have been uncovered. 

Closer look at the play of colour in a black opal from the Gem-A Archives.


Black opals have also been found in the Virgin Valley, in Humboldt County, Nevada. These opals display a very strong play of light red, blue, violet and green. The Roebling opal, 2585 ct of rough black precious opal, was found in 1917 in Virgin Valley. It displays a particularly vivid green and blue play-of-colour. It is part of the Smithsonian Museum’s collections. 

Honduras is known to have yielded black opals for centuries. Honduran black opals have a unique black colour. Mexico and most recently Indonesia have yielded some black opals. 

Famous black opals

Probably the most famous black opal in history, and the first to have been given a name, is the ‘Burning of Troy’. It owes its name to the blazing red flashes burning in the black gem. It was gifted by Emperor Napoleon to his wife Joséphine, his beloved ‘Helen’. Now lost, it was regarded as the most beautiful and most valuable black opal, weighing 700 carats. It is believed it was mined in Honduras.

Considered the world most valuable black opal, the ‘Aurora Australis’ was found in Lightning Ridge. Found in 1938, it was polished into an oval shape and weighs 180cts. It displays a vibrant play-of-colour with a dominant of red, green and blue against a black background. Dug from an old sea-bed, it has a distinctive impression of a star fish on its back. It was valued at AUD$1 M in 2005. 

The Aurora Australis opal. Image courtesy of Altmann + Cherny. 


Other famous black opals from Australia also bear poetic names and include the Black Prince, the Butterfly stone, the Fire Queen and the Pride of Australia. The largest uncut black opal was found in 1986 and named the Halley’s Comet (1,982 ct). Of all opals, black opals always commend the highest prices. As they are so desirable, paler precious opals can also be treated to appear black; composites can also be made as well as imitations. 

Black opal treatments

Some treatments are used to enhance the appearance of opals with a pale body colour and poor play-of-colour. Darkening the body colour to a darker almost black colour makes the play-of-colour stand out.

Opals can be soaked in a sugar solution for a few days then in sulfuric acid. The acid turns the sugar into carbon, leaving minute particles of black carbon in the opal. This is effective at darkening the body colour of the opal. The treatment can be detected by observing these black speckles with the 10x loupe and microscope. The dark specks of carbon are limited to a thin layer at the surface and a pale matrix can be spotted in between. The play-of-colour also appears to be very close to the surface. Transmitting light through the opal, as well as immersion in water, can also help spotting the added black particles.

Sugared black opal photographed by Pat Daly at Gem-A.


Pale coloured precious opals have also been smoked. Ethiopian smoked black opals are quite common on the market. Fine smoke particles are forced into the pores of a pale opal. This is usually done by wrapping the opal in paper and heating the paper to the point of smouldering. The combustion releases microscopic particles of soot that enter the porous material. The source of the dark coloration in the opal can be checked with transmitted light or in immersion. Black speckles can be visible with the loupe or microscope . Dark colour tends to concentrate in crazed areas (surface reaching fractures). 

Black opal composites

Black opals can also be created by making composite precious opals, namely opal doublets or triplets. Opals occur in thin seams in a matrix rock and some are too thin or fragile to be shaped and used in jewellery. They are then used to make composite materials. 

Opal doublet simulant photographed by Pat Daly at Gem-A.


These composite materials require only a thin slice of precious opal – slightly thicker for doublets (just over 2mm), wafer thin for triplets (0.5mm). 

To produce a doublet, the slice is glued to a black base material, then shaped and polished to a low cabochon. The black material varies; it can be black plastic, paste, black chalcedony, ironstone or black potch opal, which is more deceptive. This black backing shows through the thin whitish slice of precious opal and effectively makes it appear darker, enhancing the play-of-colour.

Triplets are made of thin slivers of precious opal, sandwiched between a black backing and a domed colourless material, usually made of glass or quartz. These layers are glued together with epoxy resin. 

Do black opal synthetics exist in the market? 

Many attempts have been made to produce or simulate opals. Pierre Gilson started to manufacture ‘synthetic’ opals in 1974 using the gel growth technique. It is quite convincing for white opal, less so for black. Hence the Gilson black opals are slightly less pricey than the white ones. 

Synthetic opal with a columnar structure photographed by Pat Daly at Gem-A.


Gilson opals can be detected by observation. The patches of colour seem to display a ‘lizard skin’ effect; they look pixelated. When observed from the side, the columnar structure is also very distinctive. Also, unlike natural opals, ‘synthetic’ opals do not fluoresce. Other types of ‘synthetics’ are also available. None can be fully termed synthetic as they have different physical, chemical and optical properties than their natural counterpart. 

Black opal simulants

Various simulants are also manufactured to imitate black opals, such as plastic or glass simulants. The Slocum stone, created and commercialised in the 1970s by John Slocum, is made of black glass with coloured metallic foils in lieu of play-of-colour. Bubbles and swirls typical of glass are another tell-tale. 

Black opal simulant with resin and foil photographed by Pat Daly at Gem-A.


How to care for opals

Opals are rather soft materials at about 6 on the Mohs’ scale and are therefore better suited for earrings, pendants or brooches rather than rings to prevent scratching and abrasion. Because they have water in their composition, they are also sensitive to variations in humidity and temperature. Sudden changes can cause irreversible crazing. They should not be displayed in direct sunshine. When storing them for a long time, it is advised to place a slightly moist cotton next to them to keep the relatively humidity constant. Doublets and triplets should never be soaked. 

Most opals are to some degrees porous, and some, notably hydrophane opals, are absorbent. These should therefore be cleaned only with a soft dry or damp cloth. No chemicals should be used. For that reason, one should avoid testing opals on the refractometer as the RI fluid might stain them. 


Main image: Black opal cabochon with blue and green play of colour. Photo courtesy of Cody Opal.

Author: Juliette Hibou



Last chance to register for the Gem-A Conference 2022


Press Release: October 12, 2022

Gem-A, London, United Kingdom

The Gemmological Association of Great Britain (Gem-A) is preparing to welcome gemmology professionals, jewellers, retailers, and scientists to London on Sunday, November 6, 2022, for its annual Gem-A Conference. 

This year’s one-day event, which closes for new registrations on Friday, October 28, will take place at etc.venues County Hall in London, which benefits from views over the River Thames and the Houses of Parliament. 

The day will consist of eight speakers who will deliver talks based on their respective fields of expertise, including tourmaline, peridot, natural diamonds and jade. Other talks will focus on professional skills associated with gemmology, such as pricing, historical analysis, photojournalism, and scientific detection. This year’s speakers and the titles of their talks are outlined below (alphabetical order by surname): 

  1. Richard Drucker, Gemworld International: Market Update from the GemGuide
  2. David Fisher, De Beers Group Research Centre: Current Challenges for Gemmologists in Identifying Treated and Laboratory-Grown Diamonds 
  3. Dr H. Albert Gilg, Technical University of Munich: Analysis of Gemstones in Late Medieval Crowns in Europe
  4. Joanna Hardy, Fine Jewellery Specialist: Peridot – Past, Present & Future Sponsored by Fuli Gemstones (Platinum Sponsor of the Gem-A Conference)
  5. Richard Hughes, Lotus Gemmology: Jade – China’s Gift to the World
  6. Lisa Levinson, Natural Diamond Council: Consumer Attitudes to Natural Diamonds
  7. Federico Pezzotta, Natural History Museum of Milan: Paraiba and Other Gem-Tourmaline Varieties from Mavuco, Mozambique
  8. Robert Weldon, Richard T. Liddicoat Library (GIA): The Travels and Travails of a Gemmological Photojournalist

The Gem-A Conference 2022 is supported by Platinum Sponsor Fuli Gemstones, Silver Sponsors American Gemological Laboratories (AGL) and Marcus McCallum, and Bronze Sponsors the National Association of Jewellers (NAJ), Swiss Gemmological Institute (SSEF), the Canadian Gemmological Association (CGA) and Gemworld International. 

The Gem-A Conference will conclude with the Gala Dinner, which also takes place at etc.venues County Hall. Guests will be seated for a three-course meal on the evening of November 6, alongside members of the Gem-A team and representatives from Gem-A Conference sponsors. This occasion provides more opportunities for networking in an informal setting alongside evening entertainment, which will be a surprise for attendees on the night.

Gem-A CEO Alan Hart says: “This year’s Gem-A Conference looks set to be a fantastic day of learning and networking for all our attendees. We are thrilled to welcome such a strong and experienced cohort of speakers who will provide our guests with information and insights from a breadth of gemmological perspectives. Every year, the Gem-A Conference seeks to inspire professional gemmologists and students who are starting their journeys. I would encourage anyone wanting to attend to secure their tickets quickly to avoid disappointment.”

Historically, the Gem-A Conference 2022 has been accompanied by a full day of workshops and tours, incorporating some of London’s heritage sites of gemmological significance. This year’s selection includes a private tour of the Natural History Museum, a private viewing of the Gems and Jewellery Gallery at the Victoria & Albert Museum, and a behind-the-scenes tour of the Crown Jewels at the Tower of London. All the workshops and tours on offer sold out in record time from the moment they were announced to Gem-A Members in early October 2022. 

Alan Hart adds: “Gem-A Conference workshops and tours are always popular with attendees, especially our overseas guests. From the moment we announced this year’s offering, the available spaces quickly sold out. It’s heartening to see the demand for gemmological learning and the participation of our members, especially after such a long time away from in-person events due to the pandemic. Overall, this year’s Conference is shaping up to be one of our best.” 

Elsewhere, the Association is preparing for its annual general meeting (AGM) at its London headquarters on Wednesday, October 26. Members have now been invited to cast their votes on key resolutions via Civica Election Services (CES) and peruse the Association’s audited accounts. This will allow them to have a say in the Association’s upcoming activities. 

Tickets for the Gem-A Conference 2022 cost £135 for Gem-A Members and £150 for non-members. Gem-A and GIA students can secure tickets for a discounted price of £50. Tickets for the Gem-A Conference Gala Dinner cost £95. New attendees can register here:

Further information about the Gem-A Conference 2022 can be found here:

- ENDS -

For further information, please contact

Nysa Pradhan
+44 0207 404 3334


Notes to editors:

About Gem-A 

The Gemmological Association of Great Britain, or Gem-A, is the world’s longest-established provider of gem and jewellery education. Our Gemmology Diploma evolved from the first gem course proposed for the UK jewellery trade in 1908, and our prestigious Gemmology and Diamonds Diplomas — taught in seven different languages and 26 countries around the world — are recognised globally.

Gem-A forms an international community of gem professionals and enthusiasts. We serve the interests of the gem and jewellery industries through high standards of education in our courses and our support for global gemmological research. We also provide various membership opportunities, offer high-quality gemmological instruments, and host a number of educational events throughout the year, as well as two internationally distributed publications, The Journal of Gemmology and Gems&Jewellery.

About The Journal of Gemmology

The Journal of Gemmology has been the official scientific journal of the Gemmological Association of Great Britain since it was incorporated in 1947. It is published quarterly in print and electronic formats. All Individual and Gold Corporate Members of Gem-A receive The Journal as part of their membership package. Institutional subscriptions are available to laboratories, libraries, museums and similar organisations. 

To contact the Editor-in-Chief, please direct correspondence to Brendan M. Laurs FGA at