Diamond trade
| Diamond | |
|---|---|
The slightly misshapen octahedral shape of this rough diamond crystal in matrix is typical of the mineral. Its lustrous faces also indicate that this crystal is from a primary deposit.
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| General | |
| Category | Native minerals |
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Formula (repeating unit) |
C |
| 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) |
| 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 | Conchoidal (shell-like) |
| 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 |
| 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 | |
Diamond ( /ˈdaɪəmənd/ or /ˈdaɪmənd/) is a metastable 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 standard 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 and the scientific applications in diamond knives and diamond anvil cells.
Because of its extremely rigid lattice, it can be contaminated by very few types of impurities, such as boron and nitrogen. Small amounts of defects or impurities (about one per million of lattice atoms) color diamond blue (boron), yellow (nitrogen), brown (lattice defects), green (radiation exposure), purple, pink, orange or red. Diamond also has relatively high optical dispersion (ability to disperse light of different colors).
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Wikipedia