Vermiculite (ex Kay Robertson Collection)

Item Description

A RARELY seen and unusual specimen of semi-metallic looking, chatoyant, soft silvery-tan colored Vermiculite from an obscure locality called Gravellotte in South Africa. I can't find a listing for this locality, so I'm not 100% certain on the authenticity. Vermiculite is a clay mineral, rarely seen in big crystallized specimens like this. The species is one of two members of Montmorillonite-Vermiculite Group. The piece is notably lightweight for the size - only 11.59 grams. Ex Kay Robertson Collection (#7996). 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 Welt" November-December 2017).