Graphite is a high-temperature mineral of volcanic and igneous rocks, as well as pegmatites and skarns. The mineral of the class of native elements is native carbon. The name of the mineral comes from the ancient Greek "to write". The crystal lattice of the mineral consists of parallel layers, loosely connected to each other. Therefore, when rubbing against the surface, they "slide", remaining on it, due to which graphite has been used for writing since antiquity. Natural graphite has varieties:
- densely crystalline (core)
- crystalline (scaly)
- cryptocrystalline (amorphous, microcrystalline).
Graphite is a good conductor of electricity. Like talc, it has a hardness of 1 on the Mohs scale, but is also found harder. Widely used in industry.
You can see graphite stone for sale and buy it in the Minerals of Russia online store.
General | |
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Category | Native mineral |
Formula (repeating unit) |
C |
IMA symbol | Gr |
Strunz classification | 1.CB.05a |
Crystal system | Hexagonal |
Crystal class | Dihexagonal dipyramidal (6/mmm) Hermann–Mauguin notation: (6/m 2/m 2/m) |
Space group | P63mc (buckled) P63/mmc (flat) |
Unit cell | a = 2.461, c = 6.708 [Å]; Z = 4 |
Identification | |
Color | Iron-black to steel-gray; deep blue in transmitted light |
Crystal habit | Tabular, six-sided foliated masses, granular to compacted masses |
Twinning | Present |
Cleavage | Basal – perfect on {0001} |
Fracture | Flaky, otherwise rough when not on cleavage |
Tenacity | Flexible non-elastic, sectile |
Mohs scale hardness | 1–3 |
Luster | Metallic, earthy |
Streak | Black |
Diaphaneity | Opaque, transparent only in extremely thin flakes |
Specific gravity | 1.9–2.3 |
Density | 2.09–2.23 g/cm3 |
Optical properties | Uniaxial (−) |
Pleochroism | Strong |
Solubility | Soluble in molten nickel, warm chlorosulfuric acid |
Other characteristics | strongly anisotropic, conducts electricity, greasy feel, readily marks |