Bournonite (fine ''cogwheel'' twins)

Item Description

Bournonite is a well-known and desirable lead copper antimony sulfosalt, found in many world localities, but most of these localities do not produce fine specimens. The Machacamarca District in Bolivia has for many years been a source of some of the finest examples of this beloved, yet uncommon mineral. These specimens are some of the largest, finest and most crystalographically impressive examples to come out in the last 25 years or so. This piece is a showy and aesthetic example featuring a group of highly lustrous (splendent), sharp, well-formed, metallic, bright gun-metal colored, thick tabular crystals forming wonderful "cogwheel" twins, sitting on sparkling metallic golden Pyrite matrix. The largest crystal measures 3.3 cm across. The piece actually sits on its own without the aid of a base or clay. No major damage, save the base where the piece was removed from the pocket wall. It's incredibly rare to find such a complete / undamaged Bournonite specimen from this area, especially a multi-crystal group like this with great aesthetics. Very rare and significant for what it is. Don't miss out, it's one of the better Bournonites from Machacamarca that we've had to offer in the auctions in recent months. Bournonite was named after the French mineralogist Jacques Louis, Comte de Bournon. Interestingly, Bournon elected to name the species Endellionite in honor of St Endellion, Cornwall, England, the type locality for the species, but it instead was named Bournonite by Scottish mineralogist Robert Jameson (Jamesonite). Valued at $2,500.