Turquoise

Names and Properties of Turquoise

The word 'turquoise' dates back to the 17th century and is derived from the Old French 'turquois' meaning Turkish.
The gemstone was first brought to Europe from Turkestan or another Turkic territory.
Pliny the Elder referred to the mineral as 'callais' and the Aztecs knew it as 'chalchihuitl.'
Turquoise is also known as 'fayrūzeh' in Modern Persian.
The Persian turquoise mined near Nishapur, Iran, is used as a reference for evaluating turquoise quality.
Turquoise has a maximum Mohs hardness of just under 6.
It is a cryptocrystalline mineral and rarely forms single crystals.
The color of turquoise ranges from white to powder blue to sky blue, and from blue-green to yellowish green.
Turquoise has a waxy to subvitreous lustre and is typically opaque.
Its refractive index varies from 1.61 to 1.65 with birefringence of 0.040.

Turquoise deposits begin with hydrothermal deposition of copper sulfides.
Copper is leached from a host rock and redeposited in a more concentrated form as a copper porphyry.
Turquoise forms when meteoric water percolates through the copper porphyry, oxidizing the copper sulfides.
The acidic, copper-laden solution reacts with aluminum and potassium minerals to precipitate turquoise.
Turquoise deposition usually takes place at a relatively low temperature in arid environments.
Turquoise was among the first gems to be mined and many historic sites have been depleted.
Small-scale operations, often seasonal, are still worked by hand in remote deposits.
Turquoise is sometimes recovered as a byproduct of large-scale copper mining operations.
Deposits typically take the form of small veins in partially decomposed volcanic rock in arid climates.
Iran has been an important source of turquoise for at least 2,000 years.

Turquoise has been prized as a gemstone for millennia due to its rare and valuable blue-to-green hue.
It has been used to cover the domes of palaces in Iranian architecture.
Turquoise is used in jewelry, carvings, and decorative objects.
The introduction of treatments, imitations, and synthetics has devalued turquoise in the market.
Turquoise may be peppered with flecks of pyrite or interspersed with limonite veining.
Turquoise has been used by the Egyptians since at least the First Dynasty in ancient Egypt.
Turquoise is the traditional birthstone for those born in December and is considered sacred to the Zuni and Pueblo peoples.
Turquoise has been esteemed as a holy stone, bringer of good fortune, or talisman in many cultures.
Ancient Egyptians used turquoise in grave furnishings, dating back to approximately 3000 BCE.
The goddess Hathor, associated with turquoise, was the patroness of the Serabit el-Khadim mine.

The Southwest United States, including Arizona, California, Colorado, New Mexico, and Nevada, is a significant source of turquoise.
Pre-Columbian Native Americans mined turquoise in California and New Mexico.
Cerrillos, New Mexico is believed to be the location of the oldest turquoise mines.
Arizona is currently the most important producer of turquoise by value.
Nevada has over 120 mines that have yielded significant quantities of turquoise.
Turquoise artifacts have been found in the Eastern Rhodopes in Bulgaria since the fifth millennium BCE.
China has been a minor source of turquoise for over 3,000 years.
The Lynch Station in Campbell County, Virginia was the first deposit of distinct, single-crystal turquoise discovered in 1912.

Viennese turquoise, made from precipitated aluminium phosphate coloured by copper oleate.
Neolith, a mixture of bayerite and copper(II) phosphate.
Gilson turquoise, a simulant that closely resembles true synthetic turquoise.
Dyed howlite and magnesite, common imitations of turquoise.
Other natural materials occasionally confused with or used in lieu of turquoise, such as variscite, faustite, and chrysocolla.
Gemologists use non-destructive tests to detect fakes.
Close examination of surface structure under magnification.
Natural turquoise has a pale blue background with flecks of whitish material.
Manufactured imitations have a uniform dark blue color and granular or sugary texture.
Glass and plastic imitations have greater translucency and visible bubbles or flow lines.
Historical treatments to enhance color and lustre, such as waxing and oiling.
Treated turquoise may develop a white surface film over time.
Oil and wax treatments can be restored with skill.
Finer turquoise is often glued to a base of stronger foreign material for reinforcement, known as backing.
Backing increases the durability of thinly cut turquoise.
Zachery Treatment, created by Jam.

Reference	URL
Glossary	https://harryandcojewellery.com.au/blogs/glossary/turquoise
Wikipedia	http://en.wikipedia.org/wiki/Turquoise
Wikidata	https://www.wikidata.org/wiki/Q165254
Knowledge Graph	https://www.google.com/search?kgmid=/m/0fgkh