Diamond shatter6/4/2023 ![]() ![]() (Its zincblende structure is like the diamond cubic structure, but with alternating types of atoms.) A currently hypothetical material, beta carbon nitride (β- C 3N 4), may also be as hard or harder in one form. Diamond reacts with some materials, such as steel, and c-BN wears less when cutting or abrading such material. Bulk cubic boron nitride (c-BN) is nearly as hard as diamond. Diamond is extremely strong owing to its crystal structure, known as diamond cubic, in which each carbon atom has four neighbors covalently bonded to it. Known to the ancient Greeks as ἀδάμας ( adámas, 'proper, unalterable, unbreakable') and sometimes called adamant, diamond is the hardest known naturally occurring material, and serves as the definition of 10 on the Mohs scale of mineral hardness. Unlike many other minerals, the specific gravity of diamond crystals (3.52) has rather small variation from diamond to diamond. Most diamonds are electrical insulators and extremely efficient thermal conductors. Trace impurities substitutionally replacing carbon atoms in a diamond's crystal structure, and in some cases structural defects, are responsible for the wide range of colors seen in diamond. Scientists classify diamonds into four main types according to the nature of crystallographic defects present. Diamond has a high refractive index (2.417) and moderate dispersion (0.044) properties that give cut diamonds their brilliance. ![]() The anisotropy of diamond hardness is carefully considered during diamond cutting. The precise tensile strength of bulk diamond is little known however, compressive strength up to 60 GPa has been observed, and it could be as high as 90–100 GPa in the form of micro/nanometer-sized wires or needles (~ 100–300 nm in diameter, micrometers long), with a corresponding maximum tensile elastic strain in excess of 9%. Yet, due to important structural brittleness, bulk diamond's toughness is only fair to good. Diamond is the hardest naturally occurring material known. It is a crystal that is transparent to opaque and which is generally isotropic (no or very weak birefringence). Poorly formed, cryptocrystalline, shapeless, translucentĭiamond is the allotrope of carbon in which the carbon atoms are arranged in the specific type of cubic lattice called diamond cubic. Spherical, radial structure, cryptocrystalline, opaque black Resistant to acids, but dissolves irreversibly in hot steelīoiling point = none, very low vapor pressure before decomposing in solid state Octahedral, cubo-octahedral, spherical or cubic Rarely pink, orange, green, blue, gray, or red. ![]()
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