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Chemical Formula | C | |||
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Composition | Carbon, sometimes mixed with clay | |||
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Color | Dark gray to black | |||
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Streak | Black | |||
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Hardness | 1 - 2 | |||
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Crystal Forms and Aggregates |
(Hexagonal) Crystals are uncommon, and are usually small. They consist of thin hexagonal plates or distorted clusters of flaky plates in a matrix. Long, wide, hexagonal crystals are very rare. Occurs as veins; some very large ones have been discovered. Most commonly occurs in massive form. | |||
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Transparency | Opaque | |||
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Specific Gravity | 1.9 - 2.3 | |||
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Luster | Metallic | |||
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Cleavage | 1,1 - basal | |||
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Fracture | Conchoidal | |||
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Tenacity | Brittle; thin flakes slightly flexible | |||
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Other ID Marks | 1) Has a greasy feel 2) Smudges the hands when touched 3) Is a good conductor of electricity (although it does not conduct heat well) |
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Other Names |  Black Lead, Plumbago,
Grafito,
Pencil
Ore |
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Polymorphs | Diamond, Chaoite, Lonsdaleite | |||
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In Group | Native elements ; Nonmetallic elements | |||
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All About | Graphite is rather common, but fine crystals
are rare. Most Graphite mining areas produce enormous
quantities from a single or several large veins
that produce only few good crystals. Graphite has the same chemical composition as Diamond, but the two have radically different properties. Much care should be given to a Graphite specimen. The thin crystals, although flexible, are very fragile. They will smudge if swiped against a harder surface, thus ruining a specimen. Even massive specimens should not be moved across any object, even paper, for the specimen will wear out. If handled, Graphite smudges the hands, and will smudge a paper or cardboard box if kept in one. |
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Uses | The "lead" in pencils is not lead, but graphite mixed with clay. Much mined Graphite is used as pencil fillings. Its main function, however, is as a lubricant. It has many electrical uses, primarily because it is the only nonmetal that is a good conductor of electricity. | |||
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Striking Features | Low weight, greasy feel, smudge, and low hardness | |||
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Popularity (1-4) | 1 | |||
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Prevalence (1-3) | 1 | |||
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Demand (1-3) | 1 | |||
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Distinguishing Similar Minerals |
There are quite a number of minerals similar in appearance to Graphite, but Graphite's intrinsic properties easily distinguish it. Molybdenite, commonly confused with Graphite, is heavier and not smudgy. | |||
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Commonly Occurs With |
Calcite, Quartz, Muscovite, Biotite (Marble, Limestone) | |||
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Noteworthy Localities |
Fine crystals are rare, but some famous localities are Pargas, Finland; Mount Vesuvius, Naples, Italy; Borrowdale, Cumbria, England; and the Francon quarry, near Montreal, Quebec. In the U.S., commercial deposits exist in Ticonderoga, Essex Co., New York, and in Clay Co., Alabama. Graphite is common at Franklin and Ogdensburg, Sussex Co., New Jersey, where it is found as small flakes, and occasionally in crystallized hexagonal plates. Flecks have also been found at the French Creek mine, St. Peters, Chester Co., Pennsylvania, and at Bisbee, Cochise Co., Arizona. Small flakes are abundant in the Bear Mountain area, Rockland Co., New York. | |||
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Picture Icon Links |
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Picture Links | 1. Massive Graphite vein |
