22117 - Top Beautiful Huge 4.43 Inch Calcite Crystals from South Morocco Toletanaspis The group has hardly changed

The group has hardly changed in millions of years

Proceedings of the United States National Museum 41(1870):479-484

This is a rostral tooth from a large sawfish

Orthoceras waageni

where atmospheric sulfur dioxide (a common pollutant) is present

22117 - Top Beautiful Huge 4.43 Inch Calcite Crystals from South Morocco Toletanaspis The group has hardly changedHuge and sharp crystals of calcite from a new location unpublished in the mountains of the Erich region, Morocco. Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 3 as "calcite". Other polymorphs of calcium carbonate are the minerals aragonite and vaterite. Aragonite will change to calcite over timescales of days or less at