Photos by Amin Khosroshahi, ISNA
Turquoise is an opaque, blue-to-green mineral that is a hydrous phosphate of
copper and aluminum. It is rare and valuable in finer grades and has been prized
as a gem and ornamental stone for thousands of years owing to its unique hue. In
recent times turquoise, like most other opaque gems, has been devalued by the
introduction of treatments, imitations, and synthetics onto the market.
The substance has been known by many names, but
the word turquoise was derived around the 16th century from the French language
turquie, for Iranian material which was early imported through Turkey.
For at least 2,000 years, the region once known
as Persia, has remained an important source of turquoise. This deposit, which is
blue naturally, and turns green when heated due to dehydration, is restricted to
a mine-riddled region in
Neyshabur, the 2,012-metre (6,600 ft) mountain peak of Ali-Mersai, which is
tens of kilometers from Mashhad,
the capital of
Razavi Khorasan province, Iran.
