Rough Topaz from Nigeria - 18.0 CTW
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- Clarity - Eye Clean
- Dimensions - 14.6 x 13.5 x 8.7 mm
- Weight - 18.0 CTW
- Treatment - None
- Origin - Nigeria
- Comments - None
More Information about Topaz
Topaz is an aluminium silicate mineral with varying amounts of fluorine (F) and hydroxyl (OH) which replace each other through isomorphous replacement. Extreme outer limits with only fluorine or only hydroxyl have not been reported.
As a gemstone, topaz is the birthstone of November and imperial topaz is used to celebrate the 23rd year of marriage.
| Name | Topaz |
| Varieties | Imperial Topaz, Mystic Topaz |
| Refractive Index | Varies by color, 1.607-1.649 |
| Colors | Colorless, white, gray, pale to medium blue, greenish, yellow, yellow-brown, orange, pale pink, deep pink, tan, beige, red |
| Hardness | 8 |
| Wearability | Very Good |
| Enhancements | Pink or red, may be heat treated. Most blue topaz has been irradiated and heat treated. CVD treatment (surface coating) used to create mystic topaz |
| Typical Treatments | Heat Treatment, Irradiation, Surface Coating |
| Etymology | From the Sanskrit tapas for fire, alluding to the orange color, or from Topazios, an ancient Greek name for St. John's Island in the Red Sea where the gem was said to be mined |
| Inclusions | Usually planes of two or more non-miscible liquids, each containing a gas bubble. Two and three-phase inclusions have also been noted |
Sources
Today’s major sources are Brazil, Russia, Australia, Mexico, Pakistan, United States.
Care
Due to topaz’s perfect cleavage, don’t use ultrasonic or steam systems to clean them. Both vibrations and heat could cause these gems to split. Instead, use a soft brush, mild detergent, and warm water.
Some prongs can place stress on topaz’s cleavage plane. However, an expert custom jewelry maker can set this stone properly to avoid stress. Protective settings can also minimize the strain on a topaz.
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