Mcgovernite (very rare) (ex Kay Robertson Collection)

Item Description

Mcgovernite is a very rare, complex silicate and it's one of the more interesting minerals chemically speaking as its chemical composition has the largest number of atoms in the unit cell. The formula for the species reads Mn19Zn3(AsO4)3(AsO3)(SiO4)3(OH)21. The species is has only been found at ONE locality in the world, the famous Sterling Hill Mine at Franklin, New Jersey. The species was named 1927 after the famous Franklin mineral collector, James J. McGovern. This small cabinet specimen hosts beautiful, semi-metallic layered crystals of rich bronze-copper colored Mcgovernite on typical Franklin ore matrix consisting of white Calcite, red Zincite, black Franklinite, and pinkish-brown Willemite. We photographed the piece with a Canon MP-E 65 mm macro lens to better illustrate the quality. If you collect rarities, Franklin minerals or species from the type locality, do NOT miss out on this one as few are offered on the market for sale these days. Ex Kay Robertson Collection (#7891). 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).