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Chrysoberyl
Chrysoberyl - Mineral Properties and Uses |
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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. |
Uses |
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". |
Color |
various shades of green and yellow |
Streak |
colorless |
Luster |
vitreous |
Diaphaneity |
transparent to translucent |
Cleavage |
poor, prismatic |
Hardness |
8.5 |
Specific Gravity |
3.7 - 3.8 |
Distinguishing
Characteristics |
hardness, color |
Crystal System |
orthorhombic |
Chemical Classification |
oxide |
Chemical Composition |
beryllium aluminum oxide, BeAl2O4 |
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Chrysoberyl from Lake Alaotra, Madagascar.
This specimen is approximately 1/2 inch (1.3 centimeters) across.
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Mineral photographs that appear on this page with a Geology.com copyright mark are property of Geology.com and may not be used beyond our website. If you like these photos and would like to share them with others please link to this page or email its URL. The photos were taken and composed by Ann Bryant.
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