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Quartz (var. smoky-citrine)
Specimen | Catalog Number | Locality | Weight |
---|---|---|---|
Quartz (var. smoky) | NMNH G11455 | Brazil | 19747.00 ct |
Quartz is one of the most abundant minerals in the Earth’s crust. It is the major constituent of beach sand and an important component of many types of rocks. Quartz is composed of the elements silicon and oxygen, and in its pure state is colorless. However, just small amounts of various impurity atoms can yield a range of vivid colors. The profusion of colors, patterns, and textures displayed by quartz is unmatched by any other mineral and makes it one of the most widely used gem materials. The Greeks referred to quartz as krystallos, meaning “ice,” and this name is the origin of the word crystal. Citrine (yellow to orange), amethyst (purple), rock crystal (colorless), smoky (brown to gray) and rose (pink) are some of the most common varieties of quartz. Citrine is the golden yellow to orange gem variety of quartz and is colored by impurities of iron. The name comes from the French citron, meaning “lemon,” in reference to its color. The Smithsonian has an extensive exhibit of quartz, including a range of smoky and citrine gems, on display at the National Museum of Natural History. This modified marquise-shaped gem weighs 19,747 carats and is the largest smoky citrine in the National Gem Collection. It was faceted in 1987 by Michael Gray and acquired for the Collection in 2013.