Great South Gems & Minerals

• Turquoise Nuggets •
(Arizona)

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• Turquoise Nuggets •
(Arizona)

turquoise - turquoise specimens

Turquoise is an opaque, blue-to-green mineral that is a hydrous phosphate of copper and aluminum. Turquoise has a hardness of 5 to 6, just a little harder than glass. Turquoise in its finer grades is rare and has been prized as a gem and ornamental stone for thousands of years. Due to personal preference, the natural darker blue colors appear to be more valuable than the lighter blues and the green/blue colors. I recent times turquoise, like most other opaque gems, has been devalued by the introduction of treatments, imitations, and synthetics onto the market, some difficult to detect even by experts. It is a common practice to take a Howlite and die it a turquoise color and call it turquoise. There is lots of this material on the market today.

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As a secondary mineral, turquoise forms by the action of percolating acidic aqueous solutions during the weathering and oxidation of pre-existing minerals. For example, the copper may come from primary copper sulfides such as chalcopyrite or from the secondary carbonates malachite or azurite; the aluminum may derive from feldspar; and the phosphorus from apatite. Climate factors appear to play an important role as turquoise is typically found in arid regions.

Turquoise was among the first gems to be mined, and while many historic sites have been depleted, some are still worked to this day. These are all small-scale, often seasonal operations, owing to the limited scope and remoteness of the deposits. Most are worked by hand with little or not mechanization. However, turquoise is often recovered as a byproduct of large-scale copper mining operations, especially in the United States. Iran has for at least 2,000 years been source of quality turquoise. Since at least the First Dynasty, (3000 BCE) turquoise has been mined in the Sinai Peninsula and used by the Egyptians. Pre-Columbian Native Americans mined turquoise in what is now California and New Mexico using stone tools. Turquoise is still mined in California, New Mexico and Arizona by native American Indians and cut for beautiful Southwestern-type jewelry.

Turquoise was widely used by ancient Egyptians, the Aztecs, the Persians, and in Mesopotamia, and in China. The gold burial mask of Tutankhamun was inlaid with turquoise, lapis lazuli, carnelian and colored glass. For further information on turquoise go to the on-line Wikipedia page.
See also: p-M173
See also: p-M867

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