Turquoise

Turquoise is one of the most ancient gems. Archaeologist found royal jewellery made in turquoise older than 7000 years ago. Chinese artisan carves it since 3000 year ago and is the national gem of Tibet. Is considered a stone that guarantees health, fortune and protection from evil.

In southwest US, native American tribes was used as medium of exchange, and also for jewellery and amulets. The apaches believed that turquoise enhanced a warrior’s accuracy.

The gem’s name comes from the French expression pierre turques, Turkish stone, because the gem first arrived in Europe from Turkish source.

The stone can be translucent to opaque, and has a unique light blue color. The blue is not always uniform, it’s actually often mottled and with dark splotches. It might also have veins of matrix.  The quality is judged on color, texture and absence of matrix.

The blue color is caused by the presents of copper, while the iron makes the stone look more greenish and lower the quality.

The color can be unstable, it can darken, fade or became green, depending on the other foreign substance that are absorbed from the stone.

The color changing is caused by the porous surface, that can also affect the durability. On the Mohs scale its hardness is 5 to 6, perfect to be worn but with care.

Matrix veins are often visible, even though cutters always try to fashion the final gems without it.

Turquoise gem is not so rare, but is very difficult find really high quality (that are highly priced on the market). Treatments are very common either to enhance beauty and to make them resistant to foreign agents.

Wax impregnation is the most used treatment. The wax improve luster, seal the pores and avoid contact with skin,  perfume and water; if you have any jewel in turquoise please pay attention  when you wear it: contact with sweat or cosmetics may damage them irreversibly.

Gem with light color are dye impregnated , but this technique is actually not used often, because the result looks unnatural and it doesn’t last.

The first historical source of Turquoise is Persia, but now the most important mines are in southwest US and China, where comes the specimen of highest quality.

Like any other gem , even turquoise has its synthetics and imitations. we said that the market is full of turquoise, but not of high quality samples; which is why in the ’80 was created the Gilson synthetic Turquoise. The material is produced by a ceramic method and has an artificial appearance, actually it was never widely available on the market.  Instead, the imitation are very common in the market, both natural and synthetic. The natural gems that most resemble the turquoise are: Variscite, dyed howlite and chrysocolla. Among the most widely synthetic used are glass and plastic.

dyed Howlite

Variscite

Chrysocolla