This Specimen has been sold.
2.4" Double-Terminated Calcite and Chalcopyrite on Dolomite - Missouri
This is a gorgeous, 2.4" wide association of double terminated calcite crystals, iridescent chalcopyrite crystals, all on a dolomite crystal encrusted matrix. This mineral cluster was collected from the Sweetwater Mine in Reynolds County, Missouri, a site known for its stunning mineral associations.
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.
Chalcopyrite is a brass-yellow colored mineral which is one of the most important ores of copper. When weathered chalcopyrite loses it's metallic luster, turning a gray-green color. When acids are present the tarnish can develop a red to blue to purple iridescence.
Calcite, Chalcopyrite & Dolomite
Sweetwater Mine, Viburnum Trend, Reynolds County, Missouri
Entire specimen: 2.4 x 1.6"