Turquoise is an opaque, bluish to greenish mineral. It is a hydrous phosphate of copper and aluminium. Turquoise is rare, and valuable in finer grades.
Turquoise has been valued as both a gem and ornamental stone for thousands of years. However, like most other opaque gems, turquoise has been devalued recently with the explosion of treatments, imitations, and synthetics onto the market. However, most people still value the real thing.
The name Turquoise was coined in the 16th century from the French language, either from the word for Turkish (Turquois) or dark-blue stone (pierre turquin). Turquoise is not found in Turkey, but was traded at Turkish bazaars to Venetian merchants who brought it to Europe.
Turquoise was among the very first gems to be mined by the ancients. Many historic sites have been depleted, but some are still worked — as small-scale, seasonal operations, owing to the limited scope and remoteness of the deposits. Most are worked by hand with little or no mechanization.
In the United States, turquoise is often recovered as a byproduct of large-scale copper mining operations.
Turquoise is found in Iran, Sinai Peninsula, and the southwest United States ( Arizona, California, Colorado, New Mexico and Nevada.
