Arsenopyrite pseudomorph after Pyrrhotite (rare locality specimen) (ex Kay Robertson Collection)

Item Description

Mineral specimens are very uncommon from this obscure South Dakota lead mine near Deadwood, started in the mid-1960s (MINDAT). This is a rare and aesthetic specimen featuring a 1.7 pseudomorph of arsenopyrite after sharp prismatic pyrrhotite crystals flaring off the underlying Sphalerite matrix. Small discs of tan Siderite can be seen as well. A very showy and certainly hard to find specimen of this old material. Ex Kay Robertson Collection (#9624). 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).