Calcite forms in many different geologic environments. Usually colorless or white it can occur in many tints due to the inclusion of minor constituents during formation. It has possibly more habits of occurrence than any other mineral.
Chemical composition: Ca[CO3]; Hardness: 3; Trigonal
Quartz is a crystalline form of silica. The greatest concentrations of quartz are found in silica-rich igneous and metamorphic rocks. Quartz is one of Earth’s most abundant minerals and is an essential component of granite and many other rocks. Often transparent, Quartz can be found in almost any color. Quartz has piezoelectric properties, meaning it generates an electric charge in response to pressure.
SiO2; hardness ; isometric.