Description

This bournonite group features a super  3.8 cm “cogwheel” twin across the centre of the piece, intergrown with other crystals. The steel-grey crystals are particularly sharp for Saint-Laurent-le-Minier, and have a silky metallic lustre, and almost an appearance of a patina. In very good condition, with some chipping – from the optimal display angle (first photograph), most chipping is out of view and none is distracting. This is a super display specimen of French bournonite.

Most surfaces on the underside/back of this specimen are not fresh, with minor crystallization textures visible with magnification, and other mineralization present (including microscopic pyrite crystals), indicating that the specimen detached from the host rock sometime late in the crystallization sequence at the deposit.