For overall quality, this is a very good Bournonite from Bolivia. With the new Chinese Bournonites out on the market, the Bolivian pieces get lost in the mix because the Chinese pieces are simply everywhere right now. Virtually every piece of Chinese Bournonite that I've seen feature excellent, lustrous, prismatic crystals, but the large majority of them are very badly damaged (most crystals are bashed on every side), so comparatively, this Bolivian specimen is just stunning because the quality is much better. There was a find of this relatively rare lead copper antimony sulfosalt about 6 years ago at Machacamarca, and this piece is one of the better quality pieces found, especially for a crystal this size. This piece features an attractive, sharp, doubly-terminated, tabular, metallic, silvery-grey color "cogwheel"-shaped crystals on Quartz and Pyrite matrix. The main Bournonite is complete on all sides and is simply one of the most attractive specimens of this material that I've seen recently. This material was found in very small quantities from Bolivia in such fine cogwheels. Ex. Brian Kosnar Collection.