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

Item Description

Bournonite is not a rare mineral in Bolivia, but specimens from the famous Siglo XX mine are exceedingly rare in my experience. As a matter of fact, this might be the only piece of this material that we've had to offer, period. This piece features fine quality, beautiful, sharp, metallic, bladed "cogwheel"-shaped crytals of silvery-grey Bournonite measuring up to 1.3 cm sitting on Pyrite matrix. The piece is in great shape overall, with only a few minor nicks that you can't really see with the naked eye. If you collect worldwide Bournonites or Bolivian minerals, this is a rare specimen from a locality that is best known for its fine crystallized phosphates. Ex Kay Robertson Collection (#9305). 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).