gemstone
Ruby
Corundum (Al2O3 with Chromium trace)
Hardness: 9.0 on Mohs scale; Color: Red to pinkish-red; Luster: Vitreous to sub-adamantine; Crystal Structure: Trigonal/Hexagonal; Specific Gravity: 3.97-4.05
- Hardness
- 9
- Color
- Red to pinkish-red
- Luster
- Vitreous to sub-adamantine
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Physical properties
Hardness: 9.0 on Mohs scale; Color: Red to pinkish-red; Luster: Vitreous to sub-adamantine; Crystal Structure: Trigonal/Hexagonal; Specific Gravity: 3.97-4.05
Formation & geological history
Formed under high heat and pressure in metamorphic rocks such as marble or basaltic igneous rocks. Most significant deposits formed 50-800 million years ago.
Uses & applications
Primary use is in high-end jewelry, watch bearings, and industrial lasers.
Geological facts
Rubies are the red variety of the mineral corundum; all other colors are called sapphires. The most prized color is known as 'pigeon blood' red.
Field identification & locations
Identify by its extreme hardness (scratches almost everything but diamond) and distinct red fluorescence under UV light. Commonly found in Myanmar, Thailand, and East Africa.
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