Bournonite -

mineral siarkosoli the class. Rare mineral, currently only in certain regions of the Earth. Named after the French mineralogist JL Bournona, who first identified this minera l. Tablet forms crystals, krótkosłupowe, often zbliźniaczenia; its multiple zbliźniaczenia sometimes resemble gears. Skupieniach occurs in dense and granular. Is brittle, opaque, often contains admixtures such as native silver, zinc, iron, arsenic, manganese, nickel.