gemstone
Ruby
Corundum (Al2O3:Cr)
Hardness of 9 on the Mohs scale, deep red to pinkish-red color due to chromium impurities, vitreous to adamantine luster, trigonal crystal system, no true cleavage (exhibits parting), and specific gravity around 3.99-4.00.
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Physical properties
Hardness of 9 on the Mohs scale, deep red to pinkish-red color due to chromium impurities, vitreous to adamantine luster, trigonal crystal system, no true cleavage (exhibits parting), and specific gravity around 3.99-4.00.
Formation & geological history
Forms in metamorphic rocks such as marble and gneiss, as well as igneous rocks like basalt and syenite, typically created under high-temperature and high-pressure conditions over millions of years.
Uses & applications
Extensively used in high-end jewelry (rings, necklaces, earrings), industrial laser technology, and precision watch bearings.
Geological facts
Ruby is one of the traditional cardinal gemstones. The finest rubies originate from the Mogok Valley in Myanmar (Burma) and are famous for their vibrant 'pigeon's blood' red color.
Field identification & locations
Can be identified by its extreme hardness (only second to diamond), red streak-free powder, and distinctive fluorescence under UV light due to chromium content. Commonly found in alluvial gravel deposits.
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