Diamond

Hardness: 10 (Mohs scale), Color: Typically colorless or yellow, but can be blue, green, pink, red, black depending on impurities. Luster: Adamantine. Crystal Structure: Isometric (cubic) - often forms octahedrons, dodecahedrons, and cubes. Cleavage: Perfect octahedral. Specific Gravity: 3.5-3.53.

Formation Process: Diamonds crystallize from carbon at depths of 140 to 190 kilometers (87 to 118 miles) in the Earth's mantle, within cratonic lithosphere. The temperature range for diamond formation is typically 900 to 1,300 °C (1,652 to 2,372 °F). Geological Age: Most natural diamonds are between 1 billion and 3.5 billion years old. Environments: Found primarily in kimberlite and lamproite pipes.

Industry: Abrasives, cutting tools, drilling bits, polishing agents, wire drawing dies. Jewelry: Highly valued as gemstones in rings, necklaces, earrings, and other ornamental pieces due to their brilliance and durability. Construction: Used in diamond-tipped saws and drills for cutting concrete and stone.

Diamonds are the hardest known natural material. They form under extremely high pressure and temperature conditions deep within the Earth's mantle, over billions of years. Diamonds are brought to the surface through volcanic eruptions via kimberlite and lamproite pipes. Only a small fraction of mined diamonds are gem-quality; the majority are used for industrial purposes due to their superior hardness.

Identification in the Field: While difficult to identify in raw form without specialized tools, characteristic signs in alluvial deposits include their high density (they often settle with other heavy minerals like garnet and ilmenite) and their octahedral crystal habit. They are also known for their adamantine luster and extreme hardness, which can be tested by scratching other minerals. Common Locations: Major diamond-producing countries include Russia, Botswana, Canada, Australia, South Africa, Angola, and the Democratic Republic of Congo. Tips for Collectors: Raw diamonds often appear as dull, greasy-looking stones, not the sparkling gems seen in jewelry. Field identification often involves examining heavy mineral concentrates from potential kimberlite or alluvial deposits.