This Specimen has been sold.
1.55" Iridescent Chalcopyrite, Calcite and Galena Association - Peru
This is a beautiful specimen that contains an association of iridescent chalcopyrite, calcite and sphalerite crystals. It comes from the Huanzala Mine in Peru and the entire specimen measures 1.55" tall.
Galena is a lead based mineral that is in fact the primary ore of lead, and has been used for its lead content for thousands of years. Galena typically displays a gray metallic luster and forms cubes or octahedral crystals. The chemical composition of galena is PbS.
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.