Article
Article
Amethyst
Article By:
Liddicoat, Richard T., Jr. Gemological Institute of America, Los Angeles, California.
Last reviewed:January 2021
DOI:https://doi.org/10.1036/1097-8542.027500
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- Amethyst, published October 2019:Download PDF
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The transparent purple to violet variety of the mineral quartz. Although quartz is perhaps the commonest gem mineral known, amethyst (see illustration) is rare in the deep colors that characterize fine quality. Amethyst is usually colored unevenly and is often heated slightly in an effort to distribute the color more evenly. Heating at higher temperatures usually changes it to yellow or brown (rarely green), and further heating removes all color. The principal sources are Brazil, Arizona, Uruguay, and Russia. Amethyst is often cut in step or brilliant shapes, and drilled or carved for beads. Carvings are made both from transparent and nontransparent material. See also: Gem; Quartz
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