Bisbee turquoise is one of the most famous of all turquoise. It is a byproduct from the Phelps Dodge Lavender Pit copper mine in Bisbee Arizona. The story of Bisbee is found in Turquoise in America Part Two, 1910-1990.
 
This cabochon weighs 47.8 carat and measures 3cm X 2.5cm X 1cm. It is priced at $50/ct or $2385. It is not treated and is backed. I have assigned a TG of 84  or HG.I purchased this stone from Bruce Mead who cut the stone. White spot is camera flash.