|
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 |
