Graphite

Hardness: 1-2 (Mohs scale), Color: steel gray to black, Luster: metallic to earthy, Crystal Structure: hexagonal, Cleavage: perfect basal, Specific Gravity: 2.09–2.23

Formed by the metamorphism of organic-rich sedimentary rocks (like shale or coal) or via high-temperature hydrothermal processes. It is typically found in regional metamorphic belts.

Used as a dry lubricant, in the manufacture of steel and crucibles, as pencil 'lead', in batteries (lithium-ion), and for brake linings.

Graphite and diamond are polymorphs, meaning they both consist of pure carbon but have different crystal structures. It is the most stable form of carbon under standard conditions.

Identify in the field by its very low hardness (scratches with a fingernail), greasy feel, and its ability to leave a dark gray mark on paper or skin. Commonly found in metamorphic rocks like schist, gneiss, and marble.