Native Arsenic after Silver w/ Proustite (rare) Robertson Coll.

Item Description

A rare and rich old-time pseudomorph combination from the historic mines at St Andreasberg. Both sides of the quartz slab host numerous pseudos of native arsenic after spinel-twinned silver crystals and typical shell-like globules of native arsenic. A RARE accessory are the patches of red proustite seen on both sides and the edges. Ex Kay Robertson Collection # 3994 and acquired from Al McGuinness in the mid-1960s. Kay assembled a nice suite of classics and rarities from this famed district. 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). The last mine closed in 1910. RARE and rich combination pseudomorph material from the famed locale. See the Mineralogical Record St. Andreasberg Special Issue, May-June, 2017, Vol. 48, No. 3.