Color: white, colorless, gray, red, brown, green, or black
Streak: white to grayish
Hardness: 3
Specific gravity: 2.71
Cleavage: perfect
Fracture: subconchoidal
Luster: vitreous, pearly, or dull
Crystal form: trigonal/hexagonal
Transparency: transparent to translucent
Double refraction (You can see two images through a transparent piece of calcite.)
Reacts in cool, weak hydrochloric acid.
Calcite is the main mineral in limestone and forms in seawater or in the skeletons of living creatures.
For an explanation of the properties (in bold face), click here >>