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Spinel
Specimen | Catalog Number | Locality | Weight |
---|---|---|---|
Spinel | NMNH G10558 | Tanzania | 5.78 ct |
There is historical confusion between spinel and corundum (ruby and pink sapphire) because these two gemstones have many similarities, not just their appearance. Both owe their red color to trace impurities of chromium and form when impure limestone is altered by heat and pressure, and they are commonly found side by side. Many of the world's most famous "rubies" are in fact red spinels. Pure spinel is colorless, but impurities give rise to a range of colors, most typically pink or red, but also purple, green and blue. The major sources of spinel gemstones are Burma, Sri Lanka, and Thailand, and more recently Vietnam. Other significant occurrences are Pakistan, Afghanistan, and Russia. This pink spinel is from Tanzania, and it is the first spinel from that locality in the National Gem Collection.