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Hydrous phosphate of copper and aluminum

CuAl6(PO4)4(0H)8·4H20
Copper aluminum phosphate hydroxide hydrate

Properties  Applications  Localities  Treatment  Maintenance  Simulates and synthetics  Images  Links

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Properties

CrystalTurquoise crystallises in the triclinic crystal system.
Prismatic crystals are extremely rare.
It occurs generally as microcrystalline masses, globules, veins or encrustations.
ColourPale blue to bluish green.
Specific gravity2.6 - 2.8
Hardness5-6
 Turquoise from Vielsalm
Postage stamps:
Minerals from Belgium

Applications

Good quality turquoise is used as a gemstone.
Turquoise is usually polished to cabochons.
Turquoise was already used for jewels 6000 years ago.
Turquoise is the birthstone for December.

Localities

Worldwide

Turquoise Crystal Localities

Belgium

In Belgium turquoise occurs as groups of small globules and encrustations in small cavities in massive quartz at Vielsalm (Cahay quarry) and Ottré.

Treatment

Turquoise is very often impregnated with wax or stabilized with artificial resin, to improve the resistance of the relatively soft gemstone.

Simulates and synthetics

A large mixture of simulates and synthetics is frequently offered as a cheap replacement for turquoise.

Turquoise
Simulants (see subheading Simulates).

Maintenance

With hardness 6 is turquoise a relatively soft gemstone which, treated or not, requires special care.
Turquoise is also porous and can absorb anything it touches, therefore avoid contact with cosmetics.
Turquoise is sensitive to ammoniac, caustic soda, phosphoric acid, nitric acid, hydrochloric acid, and sulfuric acid.

Images

Turquoise from Vielsalm
Turquoise from Vielsalm
Ragged turquoise
Ragged turquoise
 Turquoise as jewel in Peru
Turquoise as jewel in Peru
Links to sites with images
Turquoise The Mineral Database at mindat.org
Turquoise theimage.com

Links

Turquoise
Extensive information on turquoise on «Answers.com».
Turquoise
From Wikipedia, the free encyclopedia.
Turquoise and Turquoise Jewelry
Answers to all your questions about turquoise on «About.com».
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