Diamond Ring 3D print model

This article is about the mineral. For the gemstone, see Diamond (gemstone). For other uses, see Diamond (disambiguation). Diamond A triangular prism-shaped diamond A naturally-cut diamond crystal General Category Native minerals Formula (repeating unit) C IMA symbol Dia[1] Strunz classification 1.CB.10a Dana classification 1.3.6.1 Crystal system Cubic Crystal class Hexoctahedral (m3m) H-M symbol: (4/m 3 2/m) Space group Fd3m (No. 227) Structure Jmol (3D) Interactive image Identification Formula mass 12.01 g/mol Color Typically yellow, brown, or gray to colorless. Less often blue, green, black, translucent white, pink, violet, orange, purple, and red. Crystal habit Octahedral Twinning Spinel law common (yielding macle) Cleavage 111 (perfect in four directions) Fracture Irregular/Uneven Mohs scale hardness 10 (defining mineral) Luster Adamantine Streak Colorless Diaphaneity Transparent to subtransparent to translucent Specific gravity 3.52±0.01 Density 3.5–3.53 g/cm3 3500–3530 kg/m3 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 [2][3]

Main diamond producing countries Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, but diamond is metastable and converts to it at a negligible rate under those conditions. Diamond has the highest hardness and thermal conductivity of any natural material, properties that are used in major industrial applications such as cutting and polishing tools. They are also the reason that diamond anvil cells can subject materials to pressures found deep in the Earth.

Because the arrangement of atoms in diamond is extremely rigid, few types of impurity can contaminate it (two exceptions are boron and nitrogen). Small numbers of defects or impurities (about one per million of lattice atoms) color diamond blue (boron), yellow (nitrogen), brown (defects), green (radiation exposure), purple, pink, orange, or red. Diamond also has a very high refractive index and a relatively high optical dispersion.

Most natural diamonds have ages between 1 billion and 3.5 billion years. Most were formed at depths between 150 and 250 kilometres (93 and 155 mi) in the Earth's mantle, although a few have come from as deep as 800 kilometres (500 mi). Under high pressure and temperature, carbon-containing fluids dissolved various minerals and replaced them with diamonds. Much more recently (hundreds to tens of million years ago), they were carried to the surface in volcanic eruptions and deposited in igneous rocks known as kimberlites and lamproites.

Synthetic diamonds can be grown from high-purity carbon under high pressures and temperatures or from hydrocarbon gases by chemical vapor deposition (CVD). Imitation diamonds can also be made out of materials such as cubic zirconia and silicon carbide. Natural, synthetic, and imitation diamonds are most commonly distinguished using optical techniques or thermal conductivity measurements.