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Turquoise
CuAl
6(PO
4)
4(OH)
8*5(H
2O)
Turquoise is perhaps the first mineral recognized
as valuable for its beauty. Four turquoise bracelets adorned the mummified
arm of Egypt's Queen Zar, the second ruler from the First Dynasty, who
reigned about 5500 BC. Turquoise inlaid in Gold has been found in
archeological sites in Egypt and Sumeria. The Egyptians, Sumerians and
Aztecs all produced large quantities of beadwork from turquoise. It was used
in the Americas to decorate teeth and create arrowheads. The earliest
reported mining was at the Maghara Wadi mines in the Sinai, first mined in
about 3200 BC. These mines were worked for over 2000 years, and then
rediscovered in the mid 1800s and worked until the early 1900s. In some
areas, such as Tibet, turquoise was once valued more highly than gold. Now
it ranges from a few cents to as much as fifty dollars per carat, depending
on the size and grade.
Turquoise was a major trade item as early as the
first century AD from Persia and Afghanistan north to Siberia. It was found
in large quantities in King Tut's tomb, as well as in prehistoric
archeological sites in the Americas. The use of turquoise dates back to the
thirteenth century in China and Tibet where it was often valued above gold.
Europe and Japan did not use much turquoise until the eighteenth century.
The name "Turquoise" is thought to have come from
the word "Turquie", French for Turkey, where it was generally believed to
have come from. At this time however, most turquoise in Europe originates
from Persian and Egyptian mines. The finest turquoise originated in Persia
for thousands of years and the term "Persian Turquoise" became synonymous
with all turquoise of the highest quality, regardless of its origin. Today
the finest turquoise comes from the United States, and the term "Persian
Turquoise" is being used less and less.
Most Turquoise is now mined in the U.S., with
lesser deposits found in Iran, Tibet, China, Australia, Mexico, Peru,
Afghanistan, and Chile. Each region has its own variety based on the amount
of iron, zinc, calcium, magnesium, and manganese found in the mix. Generally,
the more copper that is found in the molecular structure, the bluer the
turquoise while the introduction of iron causes the greener varieties of
the stone. Copper, phosphorus, and aluminum mix and oxidize under extreme
heat. The introduction of silicon, time, and heat complete the mix and
harden the mineral. The iron, zinc, calcium, magnesium, or manganese present
will influence the color hardness, and amount of "spider-webbing" in the
stone.
Turquoise formed near the earth's surface is much
harder than that formed deep underground. The hardness of high quality
turquoise mined near the surface will measure about 6 on the Mohs scale,
while the chalky deposits deep underground will often measure only 2. The
determining factor is the amount of silicification in the mineral. If the
material is chalky and unusable as a gem in its natural state, it will often
be stabilized. Stabilization usually involves submerging the material in an
epoxy resin and allowing the natural capillary action of the porous stone to
draw the stabilizer through the stone. Stabilized turquoise is considered a
natural stone, and without it, much of the jewelry we see today would not
exist. Most small beads and cabs are of stabilized material. It is not
practical to make them from the higher quality material, due to the wasted
material from the cutting, grinding and polishing. Without stabilization,
turquoise will often turn green in time when exposed to moisture, therefore
some better quality stones will also be sealed.
The myths and legends surrounding turquoise are
both countless and diverse. With almost 8,000 years of use, mankind has
invented a lot of superstition about this stone. It was once thought to
prevent accidents; cure blindness; and stop internal bleeding, stomachaches,
and arthritis of the hip. It would supposedly counteract the poison from
bites and stings - even deadly encounters with scorpions and snakes. Its
color would indicate "good" or "bad", health or sickness predict weather,
indicate fidelity, and, if the right color, it would bring together the
spirits of the sky and the sea. It would protect the wearer from falling
and bring the wearer good luck and prosperity.
Copyright © 2005 by Gem And Mineral Info.com.
All descriptions and images, except where noted, are the property of
Gem And Mineral Info.com
Where noted images and descriptions are used with permission of copyright
holder as indicated.
