Chrysocolla ps. After Gypsum (rare AZ) Robertson Coll.

Item Description

Nubby chrysocolla has replaced a sharp, terminated gypsum prism on this rare and very fine pseudomorph from the Helvetia District in the Santa Rita Mts., southeast of Tucson. Probably from the old extinct Omega Mine. Ex Kay Robertson Collection # 6960 and acquired from Jean Hamel as a gift in the early 1970s. Kay is a prominent California collector, who specialized in European classics (see the article in the March-April, 2007 Mineralogical Record and the 50+ page article in the German Magazine "Mineralien Velt" November-December 2017). A rare and classic Arizona pseudo and a must for the pseudo or locality collector.