Calcite, Origin unknown.

Calcite, Origin unknown.

Calcite, CaO3, Calcium carbonate. Calcite can be  so varied in appearance  that inevitabely  it features very commonly in most collections, and my collection is no exception. This specimen is composed of scalenahedral crystals on an iron rich base. The crystals have a minor coating of an orange colour, probably iron staining. Collected  a very long time ago when I should have known better, it's origin is unknown.