RHODOCHROSITE, CHALCOPYRITE (small cabinet)

Rhodochrosite is a manganese carbonate mineral characterized by the chemical formula MnCO3. While it is rarely found in its pure form, it usually exhibits a rose-red hue, though it can also appear in various shades of pink to pale brown. The mineral leaves a white streak and has a Mohs hardness ranging from 3.5 to 4.5. Its specific gravity falls between 3.45 and 3.6. Rhodochrosite crystallizes in the trigonal system and features a structure and cleavage consistent with the carbonate rhombohedral system.

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.