gemstone
Tumbled Ruby
Corundum (Al2O3)
Hardness of 9 on the Mohs scale, deep red to purplish-red color, vitreous to adamantine luster, trigonal crystal system, no true cleavage with conchoidal fracture, specific gravity around 4.0
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Physical properties
Hardness of 9 on the Mohs scale, deep red to purplish-red color, vitreous to adamantine luster, trigonal crystal system, no true cleavage with conchoidal fracture, specific gravity around 4.0
Formation & geological history
Formed within metamorphic rocks such as marble, schist, and gneisses, as well as in alluvial gravel deposits where they have been weathered out of parent rocks over millions of years
Uses & applications
Used primarily in fine jewelry, laser technology, watch bearings, and as a prized specimen for mineral and gemstone collections
Geological facts
Ruby is one of the traditional cardinal gemstones, with its red color caused by trace amounts of chromium replacing aluminum within the crystal lattice
Field identification & locations
Can be identified in raw or tumbled forms by its extreme hardness, high specific gravity (feels heavy for its size), and characteristic red hue, frequently found in countries like Myanmar, Thailand, Sri Lanka, and East Africa
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