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Formula: C native element
Specific gravity: 2.09 to 2.23
Hardness: 1 to 2
Streak: Black to steel-grey
Colour: Black to steel-grey
Solubility: Insoluble in hydrochloric, sulphuric and nitric acid
Environments：
Pegmatites
Metamorphic environments (typical)
Hydrothermal environments
Meteorites
Graphite most commonly occurs in metamorphic environments,
where it may form a considerable proportion of the
rock. In these cases, it has probably been derived from carbonaceous material of organic origin that has been
converted into graphite during metamorphism. It can also
be found in veins, in pegmatites and in many meteorites.
It is a mineral of the
greenschist,
amphibolite and
granulite facies.
Graphite is a common constituent of
phyllite, and it also may be found in
limestone,
schist and
gneiss.
Graphite is the low pressure, high temperature paramorph of
diamond. At
200oC graphite is the stable paramorph at pressures up to about 20 kbar
(SERC).
Localities
At Seathwaite, Borrowdale, Allerdale, Cumbria, England, UK, graphite occurs as very dark brownish black masses,
opaque with a greasy lustre and a dark grey streak
(AESS).
Graphite from Seathwaite - Image
Amity, Town of Warwick, Orange county, New York, USA, is an area of
granite intrusions into
marble and associated
gneiss. The marble is
mostly composed of white crystalline calcite that often has small flakes
or spheres of graphite and
phlogopite. Graphite is a common mineral in the Franklin Marble and is present at
Amity as large flakes, microscopic crystal groups of unusual habit, and spherules with a radial internal structure
(R&M 96.5.437).
Graphite from Amity - Image
The Purple Diopside Mound, Rose Road, Pitcairn, St. Lawrence county, New York, USA, is situated in
marble. The development of veins of large crystals probably occurred as
a result of fluid penetration from a concurrent intrusion. Many of the minerals of interest to collectors formed during
this primary event, with additional species resulting from the
subsequent alteration of scapolite. There seems to be little, if any,
secondary, late-stage mineralisation present.
Graphite is fairly common as black platy crystals, rosettes of crystals, and spheres to 7 mm, most commonly
found on gieseckite crystals
(R&M 96.6.550).
Graphite from the Purple Diopside Mound -
Image
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