22116 - Top Beautiful Huge 4.22 Inch Calcite Crystals from South Morocco Nenoticidaris mercieri alternating with microgranular quartz

alternating with microgranular quartz

Acanthopyge (Perunaspis)

This specimen has a fresh cut to see its internal texture

have required a hurried analytical process that we’ll extend and complete

Bulletin of the American Museum of Natural History 232:1-127

22116 - Top Beautiful Huge 4.22 Inch Calcite Crystals from South Morocco Nenoticidaris mercieri alternating with microgranular quartzHuge and sharp crystals of calcite from a new location unpublished in the mountains of the Erich region, Morocco.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