kalsiittin
Kalsiitti, known in English as calcite, is a common carbonate mineral with the chemical formula CaCO3. It is the most stable polymorph of calcium carbonate at Earth’s surface and occurs in a wide range of geological environments. Calcite crystallizes in the trigonal crystal system and often forms rhombohedra; its habits range from granular to massive and sometimes clearly crystalline. A distinctive property is strong double refraction, especially noticeable in clear varieties such as Iceland spar, which is used in polarization experiments. Calcite forms widely in sedimentary rocks like limestone and dolostone, but also in metamorphic marble and in hydrothermal veins. It is a major constituent of cave features such as stalactites and stalagmites.
Physically, calcite has a Mohs hardness of about 3, perfect rhombohedral cleavage, and a specific gravity around
Calcite is economically important as a source of lime and cement, formed by processing limestone. It is