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:Alternate meanings: Diamond (disambiguation)
Diamond is one of the natural allotropes of carbonAlternative meaning: Carbon (computing Carbon is a chemical element in the periodic table that has the symbol C and atomic number 6. An abundant nonmetallic, tetravalent element, carbon has several allotropic forms: diamonds (hardest known mineral). Bindi (the main allotrope being graphiteGraphite is one of the allotropes of carbon. See also allotropes of carbon. Unlike diamond, graphite is a conductor, and can be used, for instance, as the material in the electrodes of an electrical arc lamp. The pi orbital electrons delocalized across th; see also allotropes of carbonAllotropes of carbon are different molecular configurations ( allotropes) that pure carbon can take. These allotropes include: diamond, lonsdaleite amorphous carbon, graphite, fullerene, carbon nanotube, carbon nanofoam (newly discovered in 1997), quasam). The hardest of naturally occurring materials, diamonds cut into multi-faceted shapes are among the most prized gemGem is short for gemstone . The GEM acronym can refer to Grenoble Ecole de Management Graphical Environment Manager The Gem is also the name of an engine made by Rolls-Royce plc, primarily for use in the AugustaWestland Lynx helicopter. Jem was a televisistones of jewelleryJewellery (spelled jewelry in American English) consists of ornamental devices worn by persons, typically made with gems and precious metals. Costume jewellery is made from less valuable materials. However, jewellery can and has been made out of almost ev, and find use in industrial applications as well.
1 Properties
Diamond is a transparent, optically isotropicIsotropic means "independent of direction". Isotropic radiation has the same intensity regardless of the direction of measurement, and an isotropic field exerts the same action regardless of how the test particle is oriented. Isotropy is also a concept in crystalThis article is about the form of solid matter. For other uses of this word, see Crystal (disambiguation . Insulin Crystals A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extend with a refractive index of 2.417, a high dispersion of 0.044, and a specific gravity of 3.52.
1.1 Hardness and crystal structure
The diamond crystal bond structure gives the gem its hardness and differentiates it from graphite.
Sometimes known as adamant, it is the hardest known naturally occurring material, scoring 10 on the old Mohs scale of mineral hardness. The material boron nitride, when in a form structurally identical to diamond, is nearly as hard as diamond; a currently hypothetical material, beta carbon nitride, may also be as hard or harder in one form. Futhermore, it has been shown 1 2 that [ultrahard fullerite (C60) (not to be confused with P-SWNT Fullerite) when testing diamond hardness with a scanning force microscope can scatch diamond. In turn, using more accurate measurments, these values are now known for diamond hardness. A Type IIa diamond (111) has a hardness value of 167 GPa (±6) when scratched with an ultrahard fullerite tip. A Type IIa diamond (111) has a hardness value of 231 GPa (±5) when scratched with a diamond tip which leads to hypothetically inflated values.
The diamond derives its name from the Greek adamas, "untameable" or "unconquerable", referring to its hardness.
Diamonds typically crystallize in the cubic crystal system and consist of tetrahedrally bonded carbon atoms. A second form called lonsdaleite with hexagonal symmetry is also found. The local environment of each atom is identical in the two structures. Cubic diamonds have a perfect octahedral cleavage, which means that they have four cleavage planes. Diamonds occur most often as euhedral or rounded octahedra and twinned octahedra known as macles. Other forms include dodecahedra and cubes. Diamonds are commonly found coated in nyf, a gum-like skin. Their fracture may be step-like, conchoidal (shell-like, similar to glass) or irregular.
