Description: Crystals of colourless topaz (9mm) on matrix Nice specimen from uncommon classic locality Size: 83 X 50 X 48mmWeight: 269grProkop Mine, Krupka, North Bohemia, Czech Republic Topaz is a common gemstone that has been used for centuries in jewellery. Its golden brown to yellow colour is classic but is confused with the less valuable citrine, which is sold under the name topaz. The blue topaz that is often confused with aquamarine is rarely natural and is produced by irradiating and then heating clear crystals. Topaz is the November Birth-stone. The structure of Topaz is controlled by a chain like structure of connected irregular octahedrons. These octahedrons have aluminium in the middle surrounded by four oxygens. Above and below the aluminium 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 the incredible size of several hundred pounds. Topaz can make very attractive mineral specimens due to their high lustre, nice colours and well-formed and multifaceted crystals.
Price: 22 AUD
Location: Doreen, VIC
End Time: 2024-11-30T19:14:59.000Z
Shipping Cost: 14.12 AUD
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Item Specifics
Returns Accepted: ReturnsNotAccepted
Shape: Natural
Product Type: Mineral Specimens
Region: Prokop Mine, Krupka, North Bohemia, Czech Republic
Material: Topaz
