gemstone
Ruby
Corundum (Al2O3 with chromium trace elements)
Hardness: 9 on Mohs scale; Color: Pinkish-red to deep blood-red; Luster: Vitreous to adamantine; Crystal structure: Trigonal; Specific gravity: 3.97-4.05
- Hardness
- 9 on Mohs scale
- Color
- Pinkish-red to deep blood-red
- Luster
- Vitreous to adamantine
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Physical properties
Hardness: 9 on Mohs scale; Color: Pinkish-red to deep blood-red; Luster: Vitreous to adamantine; Crystal structure: Trigonal; Specific gravity: 3.97-4.05
Formation & geological history
Formed in metamorphic environments like marble or amphibolite, or in igneous basalts under high temperatures and pressures.
Uses & applications
Used primarily as a precious gemstone in fine jewelry, high-end watches, and historically in early laser technologies.
Geological facts
Ruby is one of the four traditional precious gemstones alongside diamond, sapphire, and emerald. Chromium gives ruby its vibrant red color and natural fluorescence.
Field identification & locations
Identified by extreme hardness (scratches almost all minerals except diamond), vivid red streakless hue, and fluorescence under UV light. Found in Myanmar, Mozambique, Sri Lanka, and Madagascar.
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