A very rich and huge size specimen of bournonite crystals, from pocket recently found in Mina Víboras (vipers), Machacamarca (Bolivia). This sample shows numerous groups crystals with well defined faces and edges. They are rich in facets, with little presence of basal pinacoids; emphasizing the presence of the cogwheel twin (Rdelerz), classic for the species, with other polysynthetic growths. The color is gray and metallic luster is more than excellent. With some green to brown siderite lenticular crystals. A good time to get a brilliant, representative and definitive bournonite specimen. THE MAIN CRYSTAL IS: 2,5 x 1,8 x 0,7 cm.