Cristobalite (ex Mullane and Van Tichelen Collections)

Item Description

An attractive specimen of a 1.5 cm, tan, "eye" of high-temperature Cristobalite perched in highly lustrous, jet-black obsidian from an uncommon California locale - Cougar Butte, Siskiyou County. Obsidian (volcanic glass) cools too quickly to crystallize. Thus, it is unusual to see minerals attached. The "eyes" or spheres of high temperature Cristobalite (SiO2 just like Quartz) are actually the result of devitrification, or loss of silica from the obsidian. Certainly, a most unusual and uncommon specimen in good quality. Formerly in the Mullane Collection and most recently in the collection of Wouter Van Tichelen. The piece dates from the 1950s to early 1970s.