gemstone

Diamond (or Diamond Simulant)

Carbon (C) if diamond, various if simulant (e.g., Cubic Zirconia ZrO2)

If diamond: Hardness 10 (Mohs), colorless to various colors, adamantine luster, cubic crystal structure, perfect cleavage in 4 directions. If simulant: varies (e.g., CZ hardness 8-8.5).

Identified July 10, 2026More gemstone →

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Physical properties

If diamond: Hardness 10 (Mohs), colorless to various colors, adamantine luster, cubic crystal structure, perfect cleavage in 4 directions. If simulant: varies (e.g., CZ hardness 8-8.5).

Formation & geological history

Natural diamonds form deep in the Earth's mantle under extreme heat and pressure over billions of years, brought to the surface by kimberlite eruptions. Simulants are lab-created or other minerals.

Uses & applications

Jewelry, industrial cutting/grinding/drilling tools, scientific applications.

Geological facts

Diamonds are the hardest known natural material. Only a diamond can scratch another diamond.

Field identification & locations

Identified by hardness, thermal conductivity (using a diamond tester), high refractive index, and specific gravity. Natural diamonds often have inclusions visible under magnification.

Other gemstone specimens

See all

Cubic Zirconia (simulant) or Diamond

ZrO2 (Cubic Zirconia) or C (Diamond)

gemstone

Ammolite

Ammolite (Biogenic Aragonite with trace elements; fossils of Placenticeras meeki and Placenticeras intercalare)

mineral

Cubic Zirconia (or possibly Diamond)

Zirconium dioxide (or Carbon)

gemstone

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

sedimentary

Faceted Gemstone

Unknown transparent mineral, possibly Diamond (C), Cubic Zirconia (ZrO2), Quartz (SiO2), or Glass

gemstone

Milky Quartz

Silicon Dioxide (SiO2)

mineral