Diamond

This article is about the mineral. For the gemstone, see Diamond (gemstone). For other uses, including the shape ◊, see Diamond (disambiguation).
Diamond

A scattering of round-brilliant cut diamonds shows off the many reflecting facets.
General
Category Native Minerals
Chemical formula C
Identification
Molar mass 12.01 g·mol-1
Color Typically yellow, brown or gray to colorless. Less often blue, green, black, translucent white, pink, violet, orange, purple and red.
Crystal habit Octahedral
Crystal system Isometric-Hexoctahedral (Cubic)
Cleavage 111 (perfect in four directions)
Fracture Conchoidal (shell-like)
Mohs scale hardness 10
Luster Adamantine
Streak Colorless
Diaphaneity Transparent to subtransparent to translucent
Specific gravity 3.52±0.01
Density 3.5–3.53 g/cm3
Polish luster Adamantine
Optical properties Isotropic
Refractive index 2.418 (at 500 nm)
Birefringence None
Pleochroism None
Dispersion 0.044
Melting point Pressure dependent
References [1][2]

In mineralogy, diamond (from the ancient Greek αδάμας – adámas "unbreakable") is an allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is less stable than graphite, but the conversion rate from diamond to graphite is negligible at ambient conditions. Diamond is renowned as a material with superlative physical qualities, most of which originate from the strong covalent bonding between its atoms. In particular, diamond has the highest hardness and thermal conductivity of any bulk material. Those properties determine the major industrial application of diamond in cutting and polishing tools.

Diamond has remarkable optical characteristics. Because of its extremely rigid lattice, it can be contaminated by very few types of impurities, such as boron and nitrogen. Combined with wide transparency, this results in the clear, colorless appearance of most natural diamonds. Small amounts of...