Turquoise dates back well over 4000 years and was considered the “Jewel of the Orient”.
Kusam Malhotra – DCGIA President (left) & Zohreh Amini – Gemologist (right)
Turquoise was a treasured gem for Royalty of Europe, Ancient Egyptians
and the Persian Empire.
Turquoise is a nontransparent (opaque) mineral with mostly blue to green colors, the blue being prized.
Chemically Turquoise is made up of mainly hydrated phosphate of aluminum and copper, which gives it the color and matrix. Surface of fine quality turquoise is very hard and can be well polished.
Lesser quality turquoises with a chunky rough surface, cannot be polished without first treating it in a procedure known as “stabilizing”. If it has excellent color it will often be stabilized in order to make a usable product. Blocks of Turquoise are also produced by collecting dust from the cutting process of fine Turquoise and gluing it together. Only advance testing procedures can reveal that the turquoise has been reconstituted.
Major Turquoise Mines and Sources: US – China – Iran
Turquoise was initially discovered around 200 B.C. by Native American Indians in the Southwest region and used for decoration and religious purposes. Most of the Turquoise mines in the US are in Arizona and Nevada.
With Nevada being the second most important supplier. States with important production are shown in blue with minor producers in yellow.
Chinese Turquoise mining dates to before 1700 B.C. China is the world’s largest supplier of Turquoise and accounts for 60 – 80% of the Turquoise sold in the United States.
Almost all Chinese Turquoise requires stabilizing treatments. China also ranks #1 as the producer of fake gemstones.
Persia (Modern day Iran)
Persian Turquoise is well known for its clear sky blue to deep rich dark blue color. The best Persian Turquoise is produced from mines around Iran`s north eastern city of Neyshapour located 150 kilometers from the city of Mashhad in Khorasan Razavi province. There are also mines in the Damgan and Kerman regions.
The ancient Persian grading classified Turquoise into three quality groups:
Angoustari – This is the first gem quality suitable for fine jewelry. This Turquoise has a rich blue color and a minimum amount of marking or matrix.
Barkhaneh – This is the second quality turquoise with more marking and matrix.
Arabi –These stones were considered third rate due to pale blue or green color with more matrix.The Art of Persian Turquoise Inlaying:
“Firouzeh Koobi” or Turquoise inlaying on jeweler and silver, bronze and copper containers are Iranian handcrafts that are very popular in Iran.
Turquoise Inlaying is often used in Calligraphy art work.
DCGIA thanks Zohreh for sharing with our members and bringing items raffled off as part of the 50/50 Raffle.
Email: ZohrehAmini_Arf@yahoo.com – Telephone Number: 703-980-7876
Summary Charles Marts – Secretary DCGIA
Slides provided from Zohreh Amini’s presentation
Photos taken by Melanie Marts – Vice President DCGIA