BARITE, BaSO4 -  Barium Sulfate. A tight cluster of amber-brown crystals of Orthorhombic shape tabular Barite fanning out in different directions. One of the better specimens I've seen from this mine, in this size. Specimen is 4 cm (1-1/8") wide by 5 cm  (2") deep by 3.8 cm ( 1-1/") high. Pack Rat Mine, Carbon County, Montana.