Calcite: a mineral also known as “Iceland spar”. Chemically, it is Calcium Carbonate with the formula CaCO₃. Its appearance ranges from transparent to opaque, with a vitreous to greasy luster and colors from white to colorless and various hues. It crystallizes in the Trigonal System and occurs in a variety of forms, the simplest being: rhombohedron, prism, and scalenohedron, as well as tabular forms. It is the main mineral component of Limestone and Marble. As an accessory mineral, it is found in many igneous, metamorphic, and sedimentary rocks.
