Diamond (set in Gold)

Hardness: 10 (Mohs scale); Color: Colorless (as shown), but can vary; Luster: Adamantine (brilliant); Crystal Structure: Isometric-Hexoctahedral (cubic); Cleavage: Perfect octagonal; Specific Gravity: 3.52.

Formed deep within the Earth's mantle (150-250 km below the surface) under extreme pressure and high temperatures. They are brought to the surface via deep-source volcanic eruptions called kimberlite pipes. Most geological specimens are between 1 billion and 3.5 billion years old.

Primarily used in high-end jewelry (as seen in this ring) due to its brilliance and durability. Industrially used for cutting, drilling, and grinding tools because of its unmatched hardness.

Diamond is the hardest naturally occurring substance on Earth. While they are famous for jewelry, the majority of mined diamonds are actually spent in industrial applications. The most famous specimen is the Cullinan Diamond, which was over 3,000 carats uncut.

Identification in the field is difficult without lab equipment, but they are characterized by their extreme hardness (ability to scratch any other material) and high refractive index (sparkle). Commonly found in alluvial deposits or within kimberlite and lamproite volcanic tubes. Collectors look for 'indicator minerals' like pyrope garnets or chromian diopside when prospecting.