Gallena
Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver. Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms. It is often associated with the minerals sphalerite, calcite and fluorite.
Chalcopyrite
Chalcopyrite is a copper iron sulfide mineral and the most abundant copper ore mineral. It has the chemical formula CuFeS2 and crystallizes in the tetragonal system. It has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mohs scale. Its streak is diagnostic as green-tinged black. On exposure to air, chalcopyrite tarnishes to a variety of oxides, hydroxides, and sulfates. It is rarely found in association with native copper. Chalcopyrite is a conductor of electricity. Copper can be extracted from chalcopyrite ore using various methods. The two predominant methods are pyrometallurgy and hydrometallurgy, the former being the most commercially viable.
Amethyst
Amethyst is the purple variety of the quartz mineral species. It’s the gem that’s most commonly associated with the color purple, even though there are other purple gems such as sapphire and tanzanite. Its purple color can be cool and bluish, or a reddish purple that’s sometimes referred to as “raspberry.”
Calcite
Calcite is a carbonate mineral CaCO3 and the most stable polymorph of calcium carbonate (calcite, aragonite, and vaterite). The color is milky white due to transparency with a yellow tint. The luster is vitreous with a white streak. The specific gravity of the mineral is 2.71 g/cm3.
Quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO2.