The DIAMOND engineer's future coming soon
Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Diamond as a form of carbon is tasteless, odourless, strong, brittle solid, colourles…
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Properties
Diamond is a solid form of pure carbon with its atoms arranged in a crystal. Solid carbon comes in different forms known as allotropes depending on the typ…
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Geology
Diamonds are extremely rare, with concentrations of at most parts per billion in source rock. Before the 20th century, most diamonds were found in alluvial …
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Diamond
A natural diamond crystal
GeneralCategoryNative mineralsFormula
(repeating unit)CIMA symbolDia[1]Strunz classification1.CB.10aDana classification1.3.6.1Crystal systemCubicCrystal classHexoctahedral (m3m)
H-M symbol: (4/m 3 2/m)Space groupFd3m (No. 227)StructureJmol (3D)Interactive imageIdentificationFormula mass12.01 g/molColorTypically yellow, brown, or gray to colorless. Less often blue, green, black, translucent white, pink, violet, orange, purple, and red.Crystal habitOctahedralTwinningSpinel law common (yielding "macle")Cleavage111 (perfect in four directions)FractureIrregular/UnevenMohs scalehardness10 (defining mineral)LusterAdamantineStreakColorlessDiaphaneityTransparent to subtransparent to translucentSpecific gravity3.52±0.01Density3.5–3.53 g/cm33500–3530 kg/m3Polish lusterAdamantineOptical propertiesIsotropicRefractive index2.418 (at 500 nm)BirefringenceNonePleochroismNoneDispersion0.044Melting pointPressure dependentReferences[2][3]
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) can color a 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 kimberlitesand lamproites.
Synthetic diamonds can be grown from high-purity carbon under high pressures and temperatures or from hydrocarbon gases by chemical vapor deposition (CVD). Natural and synthetic diamonds are most commonly distinguished using optical techniques or thermal conductivity measurements. [citation needed]
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