Calcite

**Chemical composition:** CaCO₃

**Hardness:** 3

**Density:** 2.6‒2.8 g/cm³

**Crystal system:** Trigonal

**Luster:** ​​Vitreous to Resinous

**Info:** Calcite is the most stable polymorph of calcium carbonate (CaCO3). The other polymorph is aragonite. Coloration is white or transparent, grey, red, orange, yellow, green, blue, violet, brown, or even black. A transparent variety called Iceland spar is used for optical purposes. Calcite is a common constituent of limestone, which is formed from the shells of dead marine organisms. It is also the primary mineral in metamorphic marble or builds stalactites and stalagmites in caverns.

## Keywords
mineral calcite texture color ornamental stone semi-precious gemstone