Gratonite (incredibly rare MATRIX specimen!) (ex Kay Robertson Collection)

Item Description

Gratonite is a very rare and highly sought after lead arsenic sulfosalt. The best specimens of the species were found at the type locality, Cerro de Pasco in Peru (specifically the Excelsior Mine). Cerro de Pasco has been mined for Silver by the Spanish since 1630, and certainly prior to that by the native people of the area. This particular specimen is from the great find in the mid 1970s and is a superb full sized miniature features a 1.1 cm "spray" consisting of wonderful, sharp, metallic, silvery colored trigonal crystals, but the most important aspect is that the "spray" is on matrix! The vast majority of Gratonite specimens are off matrix, and to find a showy display specimen like this on matrix is exceedingly rare, especially these days. Valued in the inventory at $1,500. Ex Kay Robertson Collection (#9667). 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).