Calcite is a common and abundant mineral that belongs to the carbonate mineral group. It is composed of calcium carbonate (CaCO3) and forms in a variety of shapes, including rhombohedra, scalenohedra, and prisms. Its crystal structure is trigonal, with perfect cleavage along three directions, resulting in rhombohedral fragments. Calcite crystals often exhibit a remarkable optical property called double refraction, where light passing through the crystal splits into two rays, each following a slightly different path. This property makes calcite crystals particularly interesting for polarization and optical studies.In its purest form, calcite is colorless, but it can also occur in a wide range of colors, including white, yellow, orange, blue, green, and red. The colors are usually due to impurities present in the crystal lattice.
