Bensonite

This sample of Bensonite is displayed in the Smithsonian Museum of Natural History. Bensonite is a carbonate mineral which contains barium, magnesium, calcium, manganese and strontium with the general composition (Ba,Sr)₆(Ca,Mn)₆Mg(CO₃)₁₃. This sample is about 8x8 cm and originated in Hardin County, Illinois.