Bournonite (rare locality specimen) (ex Kay Robertson Collection)

Item Description

A highly aestethic big thumbnail sized specimen featuring several groups of sharp, lustrous, metallic, silvery-grey colored Bournonite crystals measuring up to 1.4 cm with minor associated Quartz. The piece is crystallized on all sides, and looks great from several angles. I love how much depth and three-dimensional appeal there is in the specimen, as we rarely see a Bournonite with aesthetics like this in any size, let alone a thumbnail. There is a slight "coghweel"-esque habit to a few of the groups, while others are simply groups of intergrown crystals in parallel growth. There is a slight overgrowth on the surface of the crystals, which could be a secondary deposition of Bournonite or possibly another sulfide / sulfosalt. Great quality, very showy and incredibly hard to find on the market. These specimens came out from what I believe is a single discovery at La Oroya in 1985. Ex Kay Robertson Collection (#10750). Kay was a prominent California collector, who specialized in European classics. She nearly lived 100 years from April 1920 - March 2020. See the article in the March-April, 2007 Mineralogical Record ( https://www.mineralogicalrecord.com/pdfs/Kay%20Robertson%20Collection.pdf ), and the 50+ page article in the German Magazine "Mineralien Welt" November-December 2017.