Diamond

Chemical Formula : C
Hardness : 10
Cleavage : Four; perfect
Luster : Admantine
Color : Pale yellow, brown, white to blue-white; also orange, pink, blue, green, red, and black
Streak : White
Density : 3.5
Diagnostic Features and Trivia : Diamond is the definition of the top of Moh's hardness scale, and also the definition of adamtine luster.
Crystal System and Habit : Isometric; common - octahedral, also dodecahedral, cubic, and tetrahedral.
Twinning : {111}; simple and multiple
Polymorphs : Graphite
Index of Refraction : 2.4195