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Quartz (var. amethyst)

Octagon-cut purple quartz (var. amethyst) weighing 401.52 ct.
Photo by Ken Larsen. Click to zoom.
Catalog Number NMNH G11438-00
Locality Bahia, Brazil
Weight 401.52 ct

Gift of Smithsonian Gem and Mineral Collectors in 2012.

Quartz is one of the most abundant minerals in the Earth’s crust. It is composed of the elements silicon and oxygen and in its pure state is colorless. Small amounts of various impurity atoms can produce a range of colors in quartz. Amethyst, the most valuable gem variety of quartz, is purple. Just a few atoms of iron replacing some of the silicon, combined with natural radiation, will cause the purple color. According to Roman mythology, amethyst was colored purple by the god of wine and was thought to offer protection against drunkenness. It derives its name from a Greek word meaning “not to intoxicate.” This magnificent amethyst gem from Brazil has not been treated in any way and displays an intense vivid purple color with flashes of red. At 401.52 carats this emerald-cut gem is the finest and one of the largest faceted amethysts in the National Gem Collection. It is a major upgrade for the Collection not only because of the size, but also because of the superb color, clarity and cut. This exceptional gem was a gift from the Smithsonian Gemstone Collectors group in 2012.

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