gemstone

Diamond

Carbon (C)

Hardness: 10 (Mohs scale), Color: Clear/Colorless, Luster: Adamantine, Crystal Structure: Cubic/Isometric, Cleavage: Perfect Octahedral, Specific Gravity: 3.52

Identified July 10, 2026More gemstone →

Explore Diamond in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 10 (Mohs scale), Color: Clear/Colorless, Luster: Adamantine, Crystal Structure: Cubic/Isometric, Cleavage: Perfect Octahedral, Specific Gravity: 3.52

Formation & geological history

Formed deep within the Earth's mantle under extreme pressure and high temperatures, then transported to the surface by kimberlite and lamproite volcanic eruptions. Most are 1-3.5 billion years old.

Uses & applications

Used extensively in fine jewelry for engagement rings and high-end pieces, and industrially for cutting, drilling, and grinding tools due to its extreme hardness.

Geological facts

Diamond is the hardest naturally occurring substance on Earth. It is composed of a single element, carbon, arranged in a crystal lattice structure that makes it incredibly strong.

Field identification & locations

Identified by its high refractive index, extreme hardness (scratches all other materials), and adamantine luster. Diamonds are commonly found in alluvial deposits or within kimberlite pipes. Collectors look for clarity, color, and cut quality.