Sainfeldite (very rare) (ex Kay Robertson Collection)

Item Description

A very hard to find specimen featuring light purplish-pink colored aggregates of the very rare hydrated calcium arsenate Sainfeldite on matrix from Richelsdorf. We have photographed the piece with a Canon MP-E 65 mm macro lens to better illustrate the quality. The label states that the piece is associated with "Guarinite", which is no longer a valid species, and according to a listing on mindat "appears to be an intergrown mixture of Clinoguarinite and Orthoguarinite, a silicate and fluoride of Na, Ca and Zr". I can see some small yellowish crystals that I believe are supposed to be the Guarinite. If you collect rarities, this is something that is virtually impossible to find on the market. Ex Kay Robertson Collection (#6905). 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).