Turquoise oagems.com


With a history of over 3000 years, turquoise was once a highly prestigious gemstone of cultures such as the Persians (Iran), Egyptians, Aztecs and Tibetans.  The highest quality turquoise has come from Iran (formerly Persia) since antiquity.  Unfortunately, this once highly esteemed stone has had its name tarnished and value diminished in recent decades due to the market being flooded with heavily treated, low quality material used in mass produced jewellery.  Although untreated fine examples of Iranian turquoise are still available, the overwhelming majority of turquoise in the market today is stabilized or treated with polymers and commonly dyed.  Because of the prevalence of this treated turquoise, it should be assumed most turquoise has been treated unless otherwise stated.  Common countries where treated turquoise originates from are: China, Mexico and U.S.A.   

Mohs’ Hardness: 5-6
Specific Gravity: 2.60-2.90
Refractive Index: 1.610-1.650
Birefringence: 0.040
Optic Sign & Character: Aggregate
Treatments: Impregnation and or dying
Incidence: Very common
Purpose: To improve colour and stability
Durability: Poor
Special Care: Avoid all chemicals
Synthetics: Reconstituted turquoise
Possible Imitations: Glass, plastic