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

Metamorphic environments (typical)
Hydrothermal environments

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).


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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