Diamond

Hardness of 10 on the Mohs scale, transparent to opaque, adamantine luster, cubic crystal system, perfect octahedral cleavage, specific gravity of 3.51.

Formed under extreme heat and pressure in Earth's mantle at depths of 140 to 190 kilometers, brought to the surface by deep volcanic eruptions of kimberlite pipes.

Widely used in high-end jewelry as gemstones, and extensively in industrial cutting, grinding, and drilling tools due to its extreme hardness.

Diamonds are the hardest known natural substance on Earth and form billions of years ago before being transported upward by ancient magmas.

Identified by its extreme hardness capable of scratching all other minerals, high thermal conductivity, and brilliant adamantine luster; commonly mined in Africa, Russia, and Canada.