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Topaz Specimens
The structure of Topaz is controlled by a chain like structure
of
connected irregular octahedrons. These octahedrons have an aluminum molecule in the
middle surrounded by four oxygens. Above and below the aluminum are the
hydroxide or fluoride ions. The chains of octahedrons are held together by
individual silicate tetrahedrons but it is the octahedron chains that give topaz
its crystalline shape. Topaz is the hardest silicate mineral and one of the
hardest minerals in nature. However it has a perfect cleavage which is
perpendicular to the chains and is caused by planes that break the weaker Al-O,
Al-OH and Al-F bonds. None of the stronger Si-O bonds cross these planes. Topaz
crystals can reach incredible size of several houndred pounds. Topaz can make
very attractive mineral specimens due to their high luster, nice colors and well
formed and multifaceted crystals.
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Beautiful colorless well-formed crystal from Yen Bai, Vietnam. Mounted in a 1"x1"1½" labelled perky box. Approx.
size: 25x11x8 Weight: 21.55 cts.
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Wonderful little well-formed colorless crystal from Yen Bai, Vietnam. Mounted in a 1"x1"x1½" perky box. This is a very
gemmy crystal and could easily be used as gem rough, but I hate to cut up such a well-formed crystal. Approx. size: 15x9x8
Weight: 11.1 cts
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Incredibly gemmy colorless crystal from Yen Bai, Vietnam with a sharp well-defined termination. This is a exceptional
specimen of this material! Approx. size: 12x11x9 Weight: 11.8 cts.
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Here's another beautiful well-formed crystal from Yen Bai, Vietnam. This one looks smokey in the photo, but it's
just a trick of the light and the crystal is actually colorless. Approx. size: 20x10x7 Weight: 12.7 cts.
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Blocky red crytal from San Luis Potosi, Mexico. Topaz from this location used to be pretty easy to find, but it
seems as though not as much is making it to the market in recent years. Approx. size: 15x14x11 Weight: 4.6 gm.
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Incredible little cluster of red crystals from San Luis Potosi, Mexico mounted in a 1½" perky box. Approx. size:
25x21x11 Weight: 4.4 gm.
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Intensely beautiful, well-formed crystal with sharp termination from Juab county, utah. Great thumbnail specimen
mounted in a 1½" perky box. Approx. size: 20x18x7 Weight: 1.7 gm.
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