Graphite

Physical Properties

Hardness: 1-2 (Mohs); Color: Iron-black to steel-gray; Luster: Metallic to earthy; Crystal Structure: Hexagonal; Cleavage: Perfect basal; Specific Gravity: 2.09–2.23; Oily or greasy feel.

Formation & Geological History

Formed through the metamorphism of carbon-rich sedimentary rocks (like coal or organic shales) under high heat and pressure, or by the reduction of carbon compounds in hydrothermal veins. Geological age varies significantly by deposit, often found in Precambrian metamorphic belts.

Uses & Applications

Used as a dry lubricant, in the 'lead' of pencils (mixed with clay), for crucibles in metallurgy, in lithium-ion batteries, and as an industrial refractory material.

Geological Facts

Graphite is the most stable form of carbon under standard conditions. While it is chemical identical to diamond, its atoms are arranged in sheets that slide easily, making it one of the softest minerals while diamond is the hardest.

Field Identification & Locations

Identify in the field by its extreme softness (scratched by a fingernail), gray streak that leaves a mark on paper, and characteristic greasy feel. Commonly found in locations like China, India, Brazil, and parts of the United States (New York).

Identified on: 4/14/2026

Mode: Standard