Bournonite was first found in the locality of Cornwall, being completely described by Jacques Louis de Bournon, a very famous French mineralogist in 1804.. It is a mineral specimen from the class of Sulfides and subclass of Sulfosalts. The color of this mineral is silver gray or black, the luster is metallic and the crystals are opaque. It is associated with other minerals such as fluorite, galena and calcite. The mineral often occurs in countries such as USA, Peru, England, Mexico and Romania. It is sold for its crystals, a 0.8cm crystal being sold for $95.