Hidden Valley is a little known mine. The story is told in Turquoise in America Part Two 1910-1990 and Part Three The Stories of Turquoise 1990-2020.
 
This cab weighs 15.5 carats and measures 2cm X 1.5cm. It is not treated and backed.It is priced at 430 a carat or $465. I have assigned a TG of 82 or HG High Grade. Hidden Valley is very rare especially at the higher grades. I purchased this stone from Wayne Nelson who sold all of Hidden Valley in the late 1970’s.