Diamond

Hardness: 10 (Mohs scale), making it the hardest naturally occurring substance. Color: Typically colorless or yellow, but can be blue, green, pink, red, orange, brown, or black due to impurities. Luster: Adamantine (brilliant, diamond-like). Crystal Structure: Isometric (cubic), commonly forming octahedrons, dodecahedra, or cubes. Cleavage: Perfect octahedral cleavage, though rarely seen in cut stones. Specific Gravity: 3.50-3.53.

Formed at extremely high pressures (45-60 kilobars) and high temperatures (900-1300 °C) in the Earth's mantle, typically at depths of 140-190 km (87-118 miles). They are brought to the surface through volcanic eruptions of kimberlite and lamproite pipes. Geological Age: Most natural diamonds are 1 to 3.5 billion years old.

Industry: Used in cutting tools, drills, abrasives, and polishing agents due to its extreme hardness. Jewelry: Highly prized as gemstones due to their brilliance, fire, and rarity. Construction: Diamond-tipped saws and drills are used for cutting concrete and asphalt.

The largest gem-quality diamond ever found was the Cullinan Diamond (3,106.75 carats). Diamonds are the birthstone for April. Colorless diamonds are graded on a D-Z scale (D being the most colorless), and colored diamonds (fancy colors) are often more valuable than colorless ones. Diamonds can also be found in meteorites.

Commonly found in kimberlite and lamproite pipes, and alluvial deposits derived from these primary sources. Major producing countries include Russia, Botswana, Canada, Australia, and South Africa. In the field, rough diamonds can be identified by their greasy luster, characteristic crystal shapes (octahedra), and extreme hardness (will scratch any other mineral). For cut diamonds, the brilliance, fire (dispersion of light into spectral colors), and hardness are key identifiers. A thermal conductivity tester is often used for positive identification, as diamonds are excellent heat conductors.