A large, superb, double pseudomorph borate crystal from the famous Death Valley of California. This sharp, lustrous and sugary crystal is colemanite pseudomorphing meyerhofferite, which itself was pseudomorphing an original large inyoite crystal. It hails from the Corkscrew Mine in Corkscrew Canyon. Very highly representative of these rare borate species and locality. Ex. John Ydren Collection.