Nevada Blue is an iconic turquoise mine considered one of the Seven Classic Mines of Nevada. The history is found in Turquoise in America Part Two 1910-1990.
 
This cabochon weighs 4.9 carats and measures 1.5cm X 1.25cm. It is priced at $70 a carat or $343. It is not treated and backed. I have assigned a TG of 92 or GG. I purchased this from Randall Marchese.