Clear Quartz
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Quartz is silicon dioxide, SiO2. Quartz is abundant in the Earth's crust, being the chemically simplest form of the silicates. All the samples here are displayed in the Smithsonian Museum of Natural History. Perhaps the first visualization of quartz is as a clear crystal, and several examples are shown here. The clear quartz gem shown at right is 353.6 carats and is from Chestnut Hill Township, North Carolina. It appears to be about 3 cm across. |  |
Clear quartz crystals come in many shapes and sizes. At left above is a column about 12x25 cm from Hot Springs, Arkansas. At center is a single crystal about 2.5x3 cm and at right is a group of crystals about 5x7 cm. These two crystals are also from Arkansas.
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 | At far left are two extremely clear crystals about 1.5x7 cm from Hot Springs, Arkansas. At near left is a very large set of crystals, about 25x30 cm, also from Hot Springs. |
 | This specimen of clear quartz is about 50x40 cm, a large cluster of crystals from Otome mine, Yamanshi, Japan. |
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This sample of quartz is about 6x10 cm and is from Middleville, New York. It is described with the phrase "Herkimer Diamond", which refers to "beautifully doubly-terminated quartz crystals already faceted by nature". More comments from the website: "The bedrock in which the crystals are found began forming approximately half a billion years ago in a shallow Cambrian sea that lapped against the southern shores of the ancestral Adirondack Mountains. They make attractive cabinet specimens, either in groups of loose crystals, singly, or in a matrix, all just as they come from the ground. The most perfect crystals, are often used as display pieces in jewelry." |  |
The quartz sample above left is about 22x22 cm and is from Guanajuato, Mexico. The sample above right is about 12x15 cm and is from Bourg d'Oisans, Isere, France.
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This large quartz sample is about 20x16 cm and is from Treasury Tunnel, Ouray, Colorado. |
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These crystal quartz gems are 654 and 358 carats. The rose quartz gem is 48.6 carats. They are from Minas Gerais, Brazil. |
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