Dims: 3.7" x 3.0" x 2.5" (9.4 x 7.6 x 6.4 cm)
Wt: 15.1 oz. (429 g)
Hardin County, Illinois, U.S.A.
This specimen from the mid-U.S. state of Illinois is made up mostly of Sphalerite by weight. The Sphalerite occurs as heavily striated tetrahedral crystals that range in size from a few millimeters to about 0.7" (1.8 cm) along an edge. The striations denote "steps" that truncate the faces and edges of each crystal, creating what could be called a hopper effect. Most of the larger crystals show some form of damage, and a few are heavily cleaved and incomplete. All of them have a nearly black coloration and an adamantine luster that is interrupted by the striations. Some of the small crystals are translucent, showing a brown coloration, but most are opaque. There is a thin crust of dolomite visible between the Sphalerites, and a few crystals are present. It is a lovely specimen tSPH-12