3.4" Golden Calcite Crystals w/ Dolomite & Herkimer Diamonds - NY

Calcite, CaCO3, is a carbonate mineral and the most stable polymorph of calcium carbonate. The other polymorphs are the minerals aragonite and vaterite. Calcite crystals are trigonal-rhombohedral, though actual calcite rhombohedra are rare as natural crystals. However, they show a remarkable variety of habits including acute to obtuse rhombohedra, tabular forms, and prisms. Calcite exhibits several twinning types adding to the variety of observed forms. It may occur as fibrous, granular, lamellar, or compact. Cleavage is usually in three directions parallel to the rhombohedron form.

Herkimer diamonds are not actual diamonds, but rather double terminated quartz crystals found in and around Herkimer County, NY. The diamond in the name is from not only their exceptional clarity, but also from the natural facets they display when found. Only crystals with these qualities found in Herkimer County, New York can be called "Herkimer Diamonds". Similar double terminated quartz crystals have also been found in abundance in Tibet and Afghanistan, but these are not true Herkimer Diamonds.

The geologic history of these crystals began 495 million years ago in a shallow sea. Waxy organic material along with quartz sand and pyrite was encased in rock made of dolomite and calcite. As sediment buried the rock and temperatures rose, crystals grew very slowly, resulting in quartz crystals of exceptional clarity. Inclusions can be found in these crystals that provide clues to the origins of the Herkimer diamonds: solids, liquids (salt water or petroleum), gases (most often carbon dioxide), two- and three-phase inclusions, and negative (uniaxial) crystals.