What is Diamond| Origins | History | Mining & Distribution | Diamond Jewels

Diamond Statistics

Composition: C (carbon)

Crystallographic Class: Cubic -- hexoctahedral (highest of the symmetries)

Space Group: Fd3m -- a = 3.57 A (cell edge)

Common Forms {indices}: F Octahedron {111}, cube {100}, dodecahedron {110}, rounded variations

Twins: Spinel-law common, yielding the flat triangular "macle"

Hardness: 10 Mohs' scale, 56-115 Knoop hardness number (GPa), 10,000 Brooks identer scale; octahedral face hardest, cube face softest

Cleavage: Excellent parallel to octahedron face -- {111}

Density: 3.51 g/cm3 (or specific gravity = 3.51)

Luster: Adamantine (diamond provides the definition for this kind of luster)

Colors: Colorless, yellow, blue, and many others

Refractive Index: 2.4175 (in the yellow light of a sodium lamp)

Dispersion: Large (0.044), leading to rainbow colors on refraction

Optical Transmission: Transparent over broad spectrum of the electromagnetic spectrum; an excellent material for optical windows

Thermal Conductivity: Superb -- 5-25 Watts/centimeter-degreesC (at 300 K); 4 times greater than copper, an excellent thermal conductor

Electrical Conductivity: 0 to ~ 100 ohm-cm (resistivity at 300 K) -- an insulator

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