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

Item Description

Bolivia literally produces thousands of tons of tin ore - mostly in the form of Cassiterite - yearly, but good specimens of Cassiterite from famous localities like the Siglo XX Mine are few and far between. This piece features fine quality, sharp, lustrous, black to slightly gemmy brown colored cyclic twins of Cassiterite measuring up to 1.2 cm across sitting on what might be Cookeite matrix. I've only seen a handful of Cassiterite specimens from this locality over the years, and this piece is a fine example for anybody who collects Bolivian minerals or worldwide Cassiterites. Ex Kay Robertson Collection (#7794). 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).