Turquoise
Turquoise is probably the most
valuable, non-transparent mineral in the jewelry trade. It was mined by
Egyptians on the Sinai Peninsula as early as 6000 BC. and was transported to
Europe through Turkey, accounting for its name, which means "Turkish" in
French.
For thousands of years the
finest intense blue turquoise in the world was found in Persia, and the term
"Persian Turquoise" became synonymous with the finest quality. This changed
during the late 1800's and early 1900's when modern miners discovered or
rediscovered significant deposits of high-quality turquoise in the
southwestern United States and Northern Mexico. The more famous mines are
the Sleeping Beauty in Globe, AZ and Turquoise Mountain in Kingman, Az., as
well as the Indian Mountain and Lander Blue mines in Nevada. An elegant sky
blue is the most valued color for gem purposes. It is said that turquoise is
like holding a piece of the sky in your hands.
Turquoise is a gemstone that
forms when water percolates through rocks that contain copper, aluminum, and
other minerals-- a process that takes millions of years. It occurs
exclusively in desert and arid environments.
The
blue in turquoise is enhanced when lots of copper is present. If the site
contains more aluminum the turquoise will shade to green. When zinc is
present the deposits are a yellow-green color, a rare combination that so
far has been found in only a few areas.
The
markings in turquoise are called the matrix. It is the stone in which the
turquoise is formed. Spider webbing refers to stones with thin lines
of matrix distributed throughout them. Black matrix may be iron pyrite.
Yellow matrix could be rhyolite. Brown is probably iron oxide.
Turquoises are relatively soft gemstones so even the finest quality receive
a waxing and subsequent hardening treatment. This procedure will make the
sensitive gemstone sturdier. Turquoise should be protected from cosmetics,
heat and bright daylight. Clean with a soft cloth and avoid harsh cleaners.
Always store jewelry in separate bags to avoid scratches. |
