Graphite is a polymorph of pure carbon known for its extreme softness and greasy feel, often leaving a black mark on paper. It typically occurs as soft, metallic-looking masses or hexagonal plates in metamorphic rocks formed from carbon-rich organic material.
Is this graphite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch graphite with a known reference. Graphite sits at Mohs 1-2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: black to steel-gray, shining.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic; may be dull, earthy.
- 4Match the color rangeCompare against the expected color range: black, steel-gray, iron black, dark gray.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: earthy, foliated, tabular.
Often confused with
Graphite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Graphite leaves black to steel-gray, shining, Molybdenite leaves bluish gray.
How to tell apart: Hematite is the harder of the two (Mohs 5-6 vs. 1-2); streak differs, so Graphite leaves black to steel-gray, shining, Hematite leaves cherry-red or reddish brown.
All properties
- Chemical formula
- C
- Mohs hardness
- 1-2
- Density
- 2.09-2.23 g/cm³
- Streak
- Black to steel-gray, shining
- Luster
- Metallic; may be dull, earthy
- Transparency
- Opaque, transparent only in extremely thin flakes
- Crystal system
- Hexagonal
- Crystal habit
- Earthy, foliated, tabular
- Cleavage
- Perfect on {0001}
- Rarity
- Common
- Uses
- Industrial, Lubricant, Writing, Collector
- Host rock
- Formed by metamorphism of sedimentary carbonaceous material, by the reduction of carbon compounds; a primary constituent in igneous rocks
Where rockhounds find graphite
15 mapped spotsClassic worldwide localities
- Monroe and Ticonderoga, Essex Co., New York, USA
- Franklin and Sterling Hill, Ogdensburg, Sussex Co., New Jersey, USA
- Commercially Quebec, at Buckingham and Grenville, and in adjacent parts, Ontario, Canada
- Nizhni Tunguski, east of Turukhansk, near the Yenisei River, Siberia, Russia
- Shunga, Karelia, Russia
- Ratnapura, Matara, and Kurunegale, Sri Lanka
Field-hunting tip
Where it forms: Formed by metamorphism of sedimentary carbonaceous material, by the reduction of carbon compounds; a primary constituent in igneous rocks. If you start seeing silicates in float, you are in the right ground. Typical habit: earthy, foliated, tabular. Train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Connecticut, New York, Tennessee. Start trip planning there.
More graphite photos
Common questions
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Find graphite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
