Ruby and Diamond in Gold Setting

Physical Properties

Ruby: Hardness 9, Deep red color, Vitreous luster, Trigonal crystal system. Diamond: Hardness 10, Transparent/White, Adamantine luster, Cubic crystal system.

Formation & Geological History

Rubies typically form in metamorphic environments (marble-hosted) or basaltic rocks. Diamonds form under high pressure and temperature in the Earth's mantle and are brought to the surface via kimberlite pipes.

Uses & Applications

Primary use in fine jewelry and as gemstones; diamonds also have industrial uses for cutting and grinding.

Geological Facts

Rubies are the red variety of the mineral corundum; any other color is considered a sapphire. Diamonds are the hardest known natural substance on Earth.

Field Identification & Locations

Identification includes checking for 'pigeon blood' red in rubies and high refractive index in diamonds. Commonly found in Myanmar, Sri Lanka, and South Africa.

Identified on: 4/21/2026

Mode: Standard