mineral

Rough Diamond

Diamond (pure carbon, C)

Hardness: 10 (Mohs scale); Color: Colorless, yellowish, or grayish; Luster: Adamantine to greasy in rough form; Crystal structure: Isometric-hexoctahedral; Cleavage: Perfect octahedral; Specific gravity: 3.52

Hardness: 10 (Mohs scale)
Color: Colorless, yellowish, or grayish
Luster: Adamantine to greasy in rough form

Identified March 22, 2026More mineral →

Identify your own rocks.

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

App Store Google Play

Physical properties

Formation & geological history

Formed under extreme pressure and temperature in the Earth's mantle, approximately 100 miles deep. They are brought to the surface through deep-source volcanic eruptions known as kimberlite or lamproite pipes. Most diamonds are between 1 billion and 3.5 billion years old.

Uses & applications

Primary use in high-end jewelry (after cutting). Industrial uses include cutting tools, drill bits, and abrasives due to extreme hardness.

Geological facts

Diamonds are the hardest known natural material. The word 'diamond' comes from the Greek word 'adamas', meaning unbreakable. Most rough diamonds found in the field look like oily or frosted pebbles rather than shiny sparks.

Field identification & locations

Identify in the field by its oily luster, crystal shape (often octahedral or rounded dodecahedral), and ability to scratch any other mineral. Found in alluvial deposits (rivers/beaches) or kimberlite pipes in locations like South Africa, Russia, Canada, and Arkansas (USA).