Diamond

Properties and Thermodynamics

Diamond is a solid form of pure carbon with a diamond cubic crystal structure.
It has the highest hardness, thermal conductivity, and refractive index of any natural material.
Most natural diamonds have ages between 1 billion and 3.5 billion years.
Synthetic diamonds can be grown from high-purity carbon under high pressures and temperatures.
The equilibrium pressure and temperature conditions for the transition between graphite and diamond are well established.
Diamond is metastable at normal temperature and pressure, with graphite being the stable phase of carbon.
Rapid conversion of graphite to diamond requires pressures above the equilibrium line.
The melting point of diamond increases with increasing pressure, but at very high pressures, it decreases.
Diamond can melt into a metallic fluid at ultrahigh pressures and temperatures.

The most common crystal structure of diamond is diamond cubic.
The unit cell of diamond has a length of 3.567 angstroms.
Diamond cubic lattice can be thought of as two interpenetrating face-centered cubic lattices.
Diamonds can also form a hexagonal diamond or lonsdaleite structure.
Diamond can have various crystal habits, including euhedral or rounded octahedra and twinned octahedra.

Diamond is a solid form of carbon with high hardness and thermal conductivity.
Diamond anvil cells can subject materials to high pressures found deep in the Earth.
Different colors in diamonds are caused by small numbers of defects or impurities.
Natural, synthetic, and imitation diamonds can be distinguished using optical techniques or thermal conductivity measurements.

Diamond is used in major industrial applications such as cutting and polishing tools.
It has high thermal conductivity, sound velocity, and low adhesion and friction.
Diamond's optical transparency extends from the far infrared to the deep ultraviolet, with high optical dispersion.
Diamond is chemically inert, not reacting with most corrosive substances, and has excellent biological compatibility.

Diamonds are extremely rare, with concentrations of at most parts per billion in source rock.
They are found in kimberlites on the oldest part of cratons, as well as in lamproites and lamprophyre rocks.
Geophysical methods like aeromagnetic surveys and electrical resistivity aid in identifying promising regions for diamond exploration.
Diamonds are dated using radioactive isotopes, with kimberlite diamonds having ages between 1 and 3.5 billion years.
Gem-quality diamonds come from depths of 150-250km in the lithosphere, specifically from mantle keels.

Reference	URL
Glossary	https://harryandcojewellery.com.au/blogs/glossary/diamond
Wikipedia	http://en.wikipedia.org/wiki/Diamond
Wikidata	https://www.wikidata.org/wiki/Q5283
Knowledge Graph	https://www.google.com/search?kgmid=/m/027_y