- In mineralogy, diamond (/daɪᵊmənd/; from the ancient Greek ἀδάμας – adámas "unbreakable") 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.
Used in so-called diamond anvil experiments to create high-pressure environments, diamonds are able to withstand crushing pressures in excess of 600 gigapascals (6 million atmospheres).
Electrical conductivity
Other specialized applications also exist or are being developed, including use as semiconductors: some blue diamonds are natural semiconductors, in contrast to most diamonds, which are excellent electrical insulators. The conductivity and blue color originate from boron impurity. Boron substitutes for carbon atoms in the diamond lattice, donating a hole into the valence band.
Substantial conductivity is commonly observed in nominally undoped diamond grown by chemical vapor deposition. This conductivity is associated with hydrogen-related species adsorbed at the surface, and it can be removed by annealing or other surface treatments
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