The birthstones
for December are the zircon and turquoise.
Zircon probably gets its name from the Arabic zar (gold)
and gun (color). This gemstone is found in igneous rocks
and comes in a variety of colors.
During the Middle Ages, zircon was worn by travelers as an amulet
for protection from sickness, injury, and insomnia.
Mohs hardness: 6.5 to 7
Refractive Index: 1.96-2.01
Specific Gravity: 4.65-4.8
The toughness of zircon is fair. They may be cleaned with steam,
ultrasonic, jewelry cleaner, soap, or an untreated cloth.
Turquoise is a soft opaque gemstone that takes a good polish and
is admired for its beautiful sky blue color. The blue color is
due to the presence of copper. Iron often provides some greener
tones. Turquoise sometimes has a rock matrix and varying shades
of grey, brown, or black veining due to inclusions or oxide stains.
Turquoise is one of the first gems ever used for jewelry. The
name of the gem is apparently related to the fact that it was
brought to Europe from the Eastern Mediterranean by Levantine
traders, generally known as Turks. It has served as an ornament
for a very long time, having been used by the Egyptians for some
thousands of years BC. Turquoise jewelry was found with a 7,500
year old Egyptian mummy. Turquoise beads from Mesopotamia (Iraq)
date back to 5000 B.C. Turquoise mining in the Americas started
about 1000 years ago. The ancient Aztecs mined it in what is now
known as New Mexico. This treasured gemstone has been discovered
in burial sites from Argentina to the Southwestern United States.
It is one of the most controversial gems because much of the material
sold has undergone so many different treatments that its original
appearance has been completely transformed.
Turquoise is found in Iran, United States (Nevada, Arizona, California,
and New Mexico), and the Sinai Peninsula.
Mohs hardness: 5-6
Refractive Index: 1.61
Specific Gravity: 2.7
The toughness of turquoise is good; however, it may be cleaned
only with pure, mild soap or an untreated cloth.
