Bisbee is a famous turquoise mine in Arizona. The history is told in Turquoise in America Part Two, 1910-1990.
 
This cabochon weighs 18.3 carats and measures 2cm X 2cm. It is not treated and backed. The price is $150 a carat or $2745. I have assigned a TG of 92 or GG. It shows the desirable smokey Bisbee look. I bought the stone from Bruce Mead.