Bisbee is an iconic turquoise no longer mined. The story is found in Turquoise in America Part Two 1910-1990.
 
This cab weight 8.8 carats and measures 2cm X 1cm. It is not treated and is backed. The price is $150 a carat or $1320. I have assigned a TG of 93 or GG. The matrix shows the rich chocolate brown very desirable in the highest grades. The stone comes from Bruce Mead. White spot is camera flash.