CHALCOPYRITE, PYRITE, QUARTZ (small cabinet)

Chalcopyrite is a copper iron sulfide mineral and the most abundant copper ore mineral. It possesses the chemical formula CuFeS2 and crystallizes in the tetragonal system. Its appearance ranges from brassy to golden yellow, with a hardness rating of 3.5 to 4 on the Mohs scale. The streak of chalcopyrite is diagnostic, displaying a-tinged black color.

Upon exposure to air, chalcopyrite undergoes tarnishing, resulting in various oxides, hydroxides, and sulfates. Associated copper minerals include the sulfides bornite (Cu5FeS4), chalcocite (Cu2S), covellite (CuS), and digenite (Cu9S5); carbonates such as malachite and azurite; and, less frequently, oxides like cuprite (Cu2O). It is seldom found in association with native copper. Chalcopyrite also serves as a conductor of electricity.

Pyrite, commonly referred to as fool's gold, is an iron sulfide with the chemical formula FeS2, also known as iron (II) disulfide. It is the most prevalent sulfide mineral found in nature.

Quartz is a robust crystalline mineral made up of silica, or silicon dioxide. Its structure consists of a continuous arrangement of SiO4 silicon-oxygen tetrahedra, where each oxygen atom is shared between two tetrahedra, resulting in the chemical formula SiO2. This classification places quartz as a framework silicate mineral in terms of structure and as an oxide mineral in terms of composition. It ranks as the second most prevalent mineral in the continental crust of Earth, following feldspar.

Private Peruvian Collection. Very rare as the mines are closed for decades. Former Steve Moon Collection.