CHALCOPYRITE, PYRITE, MANGANO CALCITE, SPHALERITE with 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.

Manganoan calcite, also known as manganocalcite, is a manganese-rich variety of calcite that exhibits a pink hue. Its chemical composition is represented by the formula (Ca,Mn)CO3. Initially identified in the Banská Štiavnica Mining District of the Slovak Republic, this mineral is found globally, with notable occurrences in the Cave of Swords in Naica, Chihuahua, Mexico, and in Bulgaria.

There is often confusion between manganoan calcite and rhodochrosite due to their similarities. The manganese content in manganoan calcite can vary by location, and it exists in a solid solution series with calcite and rhodochrosite, resulting in a deeper red color as the manganese concentration increases.

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.

Sphalerite, a sulfide mineral represented by the formula (Zn, Fe)S, serves as the primary source of zinc. This mineral occurs in various types of deposits, predominantly in sedimentary exhalative, Mississippi-Valley type, and volcanogenic massive sulfide formations. It is commonly found alongside other minerals such as galena, chalcopyrite, pyrite, and various carbonates and silicates, including calcite, dolomite, quartz, rhodochrosite, and fluorite.

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 specimen because the mines are closed for decades. Former Steve Moon Collection.