Turquoise is a blue to bluish-green mineral .It is a aluminium copper phosphate (Hydrated phosphate of copper and aluminium). It is also known as the Robin's Egg blue gemstone, because of its characteristic colour. Its colour is so characteristic that people use the term turquoise like to refer to a colour grade similar to that of turquoise.
There is a misconception about turquoise. Turquoise is not found in Turkey. The name is probably derived from Turkey because the Turkish merchants and dealers took these gemstones to Venice for sale.
Turquoise has a hardness of 5-6 on the Mohs scale, therefore it is much softer than Quartz. It has a similar hardness as Moonstone. There is hard and soft turquoise. Soft turquoise is found deep in the earth where it has not yet dried properly. Hard turquoise is found closer to the surface, because it has a chance of drying.
Turquoise is probably the most ancient gemstone used by man. Turquoise has been associated with all the ancient civilizations, archaeological excavations have found turquoise jewelry dating back as far as 3000 BC. Turquoise was also found in King Tutankhamun's tomb. The infamous burial mask of King Tutankhamun's tomb was also inlaid with turquoise.
Turquoise gemstones are usually cut en cabochon because of its relative softness. Turquoise can be polished easily and gives a good shine after polishing.
The blue colour is due to the presence of copper, the intensity of the blue colour depends on the copper content. If turquoise contains Zinc it gives a yellow-green shade to the blue colour. Iron if present gives a greenish shade to the Turquoise. Chrome can also give a greenish shade to the turquoise.
Clear blue turquoise is the best turquoise for jewelry setting and has high demand. The greenish turquoise found in India is also used in jewelry.
Turquoise is formed by water percolating thorough minerals that contain copper , aluminium .
Turquoise demands extra care because it is a soft gemstone with a mohs hardness scale of about 5-6.
Care has to be taken not to drop large turquoise gemstones or jewelry which can result in fracture, scratches or even in rare instances breaking into numerous pieces.
Never use an ultrasound cleanser to clean turquoise gemstones or jewelry set with turquoise.
Do not clean turquoise with commercial jewelry cleaners, do not spray perfumes on turquoise.
Do not wear a turquoise gemstone while swimming or bathing.
Clean turquoise only with lukewarm water and ensure that it is thoroughly dry before you store it in your jewelry box or cupboard.
Turquoise was thought by Persians to protect the wearer from poverty. Turquoise was also thought to protect against evil eye.
Turquoise is also thought to protect against the dangers of darkness and protection against unnatural death. Therefore turquoise is used as a talisman by many people.
Turquoise is thought to relieve a depressed person and is therefore used in modern gemstone therapy for this purpose.
Turquoise being among the oldest gems to be mined are found in Iran, Egypt, India, China ,Tibet, Afghanistan, Australia.
The major source of high quality sky blue turquoise for nearly 3000 years is Iran. Iranian turquoise was probably among the first turquoise to reach Europe via Turkish merchants.
Mining of turquoise in the Sinai mountain region of Egypt has been going on for thousands of years. Since the large scale mining of turquoise is not profitable, presently only a few Bedouins. The colour of the Egyptian turquoise is greener than the Iranian turquoise but is considered more durable.
The south-western states of the United States of America are famous for large turquoise deposits.
The states famous for turquoise deposits are California, Nevada, Arizona, Colorado and New Mexico. California even has pre-historic mines of Turquoise.
Although high quality turquoise have been found in American mines, in general American turquoise is of low quality and hardness (sometimes referred to as chalk turquoise)
Turquoise gemstones can be used for carvings used in ornaments and jewelry. Turquoise is cut en cabochon and set in jewelry.
Turquoise is also used as a talisman by many people.
There are numerous imitations of turquoise in the market so you have to be careful while buying turquoise. Always buy turquoise from a well established reputable jewelry firm or merchant.
Imitation turquoise is so common that it probably outnumbers genuine turquoise.
Imitation Turquoise can be easily detected by gemmologists using a number of tests. These tests include destructive and non-destructive tests. Non-destructive tests include observation under high magnification and testing of physical properties such as specific gravity, refractive index and light absorption.
Destructive tests include the use of a heated metal, that will cause it to melt if it is plastic and give the characteristic smell of plastic. Another destructive test that can be used is the application of dilute hydrochloric acid which will cause effervescence if it is made up of carbonate.
Yes, treated turquoise is widely available in most jewelry shops, and in most cases not disclosed to the customer. This is because of the inability of the mines to cope with the commercial demands for the gemstone. Most of the mined turquoise is of the softer inferior variety sometimes referred to as chalk turquoise.
The softer turquoise can to treated to make it more durable and harder while enhancing its colour.
Some of the treatments presently in use are waxing and oiling, stabilization, dyeing, reconstitution, Zachary process and backing.
Dr Shihaan Larif
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