This piece features two “cogwheel” twins of bournonite intergrown together. The bournonite crystals are sharp and lustrous, with mirror-bright striated prism faces. In excellent condition, one tiny nick and some spots of interrupted growth at the periphery, A very fine specimen of classic twinned 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.