Sphalerite

When one thinks of  specimens from the Cave in Rock locality we generally think of fluorites and galenas and occasionally calcites. Secondarily, strontianite, witherite, barite. A sphalerite specimen is not common, although many specimens have sphalerite as an association. Here, we see a gorgeous 1.6cm twinned crystal centering a pile of sharp black sister crystals. Ex Jim and Paula Wilson.

Locality: Cave in Rock, Hardin County, Illinois

Composition: zinc sulfide