Birnessite (rare) (ex Kay Robertson Collection)

Item Description

Birnessite is a rare calcium sodium manganese oxide which was named after the type locality at Birness, Scotland. This is a hard to find example of the species from the famous Poudrette Quarry at Mont Saint-Hilaire. Sharp, well-formed, black, doubly-terminated, prismatic Birnessite crystals are accented by "flower"-like groups of white Albite. This locality is now off limits for collecting, so pick up any Mont Saint-Hilaire specimens when they're available, because they will dry up in no time. Ex Kay Robertson Collection (#10308). 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).