A cluster of exquisite, sharp bournonite crystals. They exhibit classic “cogwheel” twin form, and the one at the left/top (as oriented in the first/second photographs, respectively) shows the essentially-cruciform shape depicted in classic textbook drawings. The crystals have good lustre and the prism faces are mirror-bright. In excellent condition, no damage visible from the optimal display angle (one incomplete crystal on the lower/outer left periphery, as oriented in the first/second photo, respectively). A super bournonite!
About These Bolivian Bournonites
These bournonite crystals are from the Viboras Mine, Machacamarca District, Potosí, Bolivia. The locality has produced excellent bournonite specimens over the years, but the finds are have been sporadic, often years apart. The nature of the bournonite has varied from one find to the next, and some of the bournonite has been of modest lustre, sometimes dull, and of varying sharpness/definition. This latest find has produced sharp, lustrous bournonite crystals of the finest quality, exhibiting the classic “cogwheel” twinning.