Birthstone Guide: Turquoise For Those Born In December

The beautiful and enchanting gemstone turquoise is one of three birthstones for December, enriched with cultural significance and ancient medieval lore. Join us as we explore the blue hues of this gemstone in our final birthstone round-up of 2017.

One of the first gemstones to be mined and used in jewellery, turquoise is one of three birthstones for the month of December. Admired since ancient times, this gemstone is known for its beautifully unique colour, ranging from powdery blue to an unrivalled 'robin's egg' blue. Its colour and historic significance have resulted in turquoise becoming a favourite of many.


Displaying the different properties of turquoise: cut, clarity, colour and carat weight. Photos ©Gem-A

Overview

Gem turquoise is a polycrystalline copper material typically occurring in thin seams or small nodules. Turquoise is found in dry, barren, arid regions where copper, leached from rocks by rainwater, reacts with aluminium and phosphorus. The result of this reaction is a porous, semi-translucent to opaque compound of hydrous copper aluminium phosphate with some evidence of iron. Copper produces the blue hues whilst chrome and iron add tonal variations of green.

Quite often, small patches or veins of brown or black host rock, known as matrix can be seen in the stone. The presence of these 'spider-web' patterns can often lower the value of the stone. However, some buyers actively seek stones with a presence of its matrix as they can be more unusual and attractive.

In terms of market-value, turquoise stones completely free from traces of matrix command a higher value, whilst those with evident spider-web patterns classified as desirable fetch second-place value in the trade.


Turquoise simulant; paste. Photo courtesy of Pat Daly.

Localities

The earliest evidence we have of this gemstone dates back to 3000 BCE, under the reign of King Tut, within the oldest turquoise mines located in the Sinai Peninsula of Egypt. Extraordinary pieces with elaborate displays of turquoise were found on the gold jewellery of many Egyptians, with the most extravagant display found set on the iconic burial mask of King Tut himself.

Ancient Persians believed that turquoise guaranteed protection and adorned many of their palace domes with the sky blue gemstone which they considered to represent heaven. Additionally, ancient Persians often engraved Arabic script into turquoise which would then be used to intricately decorate their daggers and horses' bridles. The highly prized 'robin's egg' blue - also known as 'Persian turquoise' - was venerated by the people of Persia (now known as Iran) as well as Siberia, Tibet, Turkey and Afghanistan. It was the Turkish traders who later introduced this 'Persian blue' stone to Europe in the 13th century through the Silk Road.

Map of localities where turquoise is found throughout the world.

Properties

The texture of turquoise is a direct result of its composition and structure. As an aggregate, polished turquoise with a smooth waxy lustre has a tightly-packed crystal structure, low porosity and a fine texture. Turquoise gems displaying a dull lustre when polished have a coarser texture and increased porosity due to a less-dense internal crystal structure. This range in texture and porosity not only directly affects the overall appearance and lustre of this gemstone but also influences its durability.

Typically, turquoise is a fairly soft stone which made it a popular choice for talisman carving across ancient history. Throughout America, many carvers fashioned turquoise into amulets of Native American significance such as birds and animals.


Collection of turquoise stones. Photo courtesy of Pat Daly.

With a hardness of 51/2 - 6 on the Mohs scale and a fairly good toughness, turquoise is a suitable material in the use of jewellery. That being said, the toughness of turquoise is significantly less in stones of a coarser texture. This December birthstone is sensitive to direct sunlight and natural solvents such as perfume, oils and makeup products. Due to its porosity, turquoise that is polished and faceted for commercial jewellery is often treated with paraffin compounds in order to increase its durability by oiling or waxing the surface of the stone.

Ancient History and Lore

Turquoise has been continuously admired as a stone of considerable meaning and sentiment across many cultures for thousands of years. As one of the world's most ancient gemstones, this highly esteemed stone has been used to decorate many artefacts from jewellery to ceremonial masks.


Turquoise simulant; Dye-treated magnesite. Photo courtesy of Pat Daly.

Archaeological evidence shows that not only was this gemstone used to embellish ancient Egyptian ornaments but was also a primary carving material for Chinese artisans. For many Native Americans, turquoise held great ceremonial value in being an instrument of exchange between tribes. As the national stone of Tibet, turquoise is enriched with ancient lore of being a symbol of good health, fortune and success. Often referred to as a token of protection, turquoise was commonly worn to ward off the presence of evil spirits, granting its wearer a sense of power.

All photos courtesy of Pat Daly at Gem-A.

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 Surface patterns and textures of different cabochons of turquoise. Images courtesy of Pat Daly ©Gem-A.


The Gems&Jewellery Autumn 2019 Issue Has Landed!

The Gems&Jewellery Autumn 2019 Issue Has Landed!

We are pleased to announce that the Autumn 2019 issue of Gems&Jewellery magazine is now available to Gem-A Members and students in print and online.

Read more


Understanding Spinel: The Alternative August Birthstone

Understanding Spinel: The Alternative August Birthstone

The varied hues of spinel have been admired for hundreds of years, but this gemstone only recently found its place on the list of ‘alternative birthstones’. Here, Lily Faber FGA DGA EG explores the alternative birthstone for the month of August and some of its synthetic counterparts.

Read more


Birthstone Guide: Peridot for Those Born in August

Birthstone Guide: Peridot for Those Born in August

Those born in August have vibrant green peridot as their birthstone. Lily Faber FGA DGA EG delves into this zesty gemstone to find out more about its physical properties and fascinating history.

Read more


5 Things to Consider Before Starting the Gemmology Foundation Course

5 Things to Consider Before Starting the Gemmology Foundation Course

Do you have a passion for diamonds, gemstones and the science of gemmology but have no idea where to start? Take a look at our guide to the Gem-A Gemmology Foundation and the things you should consider before taking this highly respected beginner’s gemmology course.

Read more


Understanding Tanzanite

Understanding Tanzanite

Our series of discovery into the Gem-A Gemstone & Mineral Collection continues with the brilliantly eye-catching tanzanite. Gem-A assistant gemmology tutor, Charles Bexfield FGA, delves into the history and unique properties of tanzanite and explores what makes this relatively new gemmological find so special. 

Read more


What Career Paths Can Trained Gemmologists Take?

What Career Paths Can Trained Gemmologists Take?

Are you fascinated by a career that utilises a gemmology skill set? Or perhaps you have completed your Gem-A Gemmology Diploma and want to know what’s next? Take a look at our guide to the opportunities open to gemmologists… you may be surprised!

Read more


Top 5 Most Famous Diamonds for Gemmologists

Top 5 Most Famous Diamonds for Gemmologists

Although all diamonds are special, there are some that are historically significant, spectacularly large and hugely important for gemmological research. Here, Rona Bierrum FGA DGA EG pinpoints the five diamonds that stand out from the crowd for gemmologists the world over. 

Read more


Gem-A's Gem Empathy Award Returns for 2019

Gem-A's Gem Empathy Award Returns for 2019

Gem-A is delighted to announce the return of the Gem Empathy Award for 2019, featuring a 12.9 carat precious coral cabochon as the prize stone. Find out more about this year's competition, and how to enter, here...

Read more


The History of Cardinal Mazarin's Extraordinary Diamond Collection

The History of Cardinal Mazarin's Extraordinary Diamond Collection

The Mazarin diamonds were a collection of 18 diamonds left to Louis XIV and the French Crown Jewels by Cardinal Jules Mazarin. Discovering the story of this group of diamonds, the man who collected them and what happened to them is like an incredible work of fiction. Charlotte Pittel FGA DGA takes us through their fascinating history.

Read more


The History of Queen Victoria's Sapphire and Diamond Coronet

The History of Queen Victoria's Sapphire and Diamond Coronet

Queen Victoria famously shared a love of fine jewels and coloured gemstones with her beloved husband, Prince Albert. In fact, one of her most prized possessions - a sapphire and diamond coronet - was designed and commissioned by Prince Albert in 1840. Here, we delve into the story behind this beautiful piece of history.

Read more


Birthstone Guide: Ruby for Those Born in July

Birthstone Guide: Ruby for Those Born in July

Those born in July can call the resplendent ruby their birthstone. To find out more about this historically significant and commercially successful gemstone, we asked Gem-A tutor Lily Faber FGA DGA EG to share her insights.

Read more


Exploring the Newest Jewelled Treasures of the V&A

Exploring the Newest Jewelled Treasures of the V&A

After 10 years and 4.2 million visitors, The Victoria & Albert Museum (V&A) has reopened its William and Judith Bollinger Gallery, home to its jewellery collection, after a three-month refurbishment with eighty new pieces joining the display.

Read more


Buying Guide: Saltwater versus Freshwater Pearls

Buying Guide: Saltwater versus Freshwater Pearls

Treasured the world over for their timeless elegance, lustre and iridescent, multi-tonal colours, pearls have for hundreds of years been a favourite of high-end jewellers and collectors alike. But how can you tell the difference between saltwater and freshwater pearls? And what should we look for when buying?

Read more