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Chrysoberyl
Chrysoberyl
Mineral Properties and Uses
What is Chrysoberyl?
Chrysoberyl is a rare beryllium aluminum oxide mineral found in granites, pegmatites and mica schists. It is resistant to abrasion and chemical attack and is often found in the sediments derived from weathering of its source rocks. It is occasionally used as a gemstone.
Physical Properties of Chrysoberyl |
| Color |
various shades of green and yellow |
| Streak |
colorless |
| Luster |
vitreous |
| Diaphaneity |
transparent to translucent |
| Cleavage |
Poor, prismatic |
| Mohs Hardness |
8.5 |
| Specific Gravity |
3.7 - 3.8 |
| Distinguishing Characteristics |
hardness, color |
| Chemical Composition |
beryllium aluminum oxide, BeAl2O4 |
| Crystal System |
orthorhombic |
Uses of Chrysoberyl?
Chrysoberyl is used as a gemstone. The typical yellow and green colors are lower-value stones. Sometimes a small amount of aluminum in chrysoberyl is replaced by chromium. This yields stones that are strongly pleochroic and change color from red to green depending upon the angle of viewing. Some also change color depending upon the type of light (natural or incandescent) that illuminates them. These stones change color from red to green and are referred to as "Alexandrite". Some yellow chrysoberyls are translucent and contain aligned inclusions of rutile. This gives them a silky luster and a chatoyance or "cat's eye". These stones are known as "cymophane".
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| Chrysoberyl from Lake Alaotra, Madagascar. This specimen is approximately 1/2 inch (1.3 centimeters) across. |
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