These calcite crystals on sphalerite are from the Denton Mine, Harris Creek Sub-District, Hardin County, Illinois, USA. Seven different minerals have been identified at this mine including sphalerite and calcite. Sphalerite is a sulfide that contains the elements Zn and S. Calcite is a carbonate that contains the elements Ca, C and O. This piece consists of flattened or foliated sphalerite crystals that host dozens of scalenohedral calcites . It measures approximately 4 1/8 x 2 1/2 x 2 1/4 inches 114 x 64 x 57 mm.