About
Chrysoberyl can exhibit a floating light reflection that moves as when a polished gem is rotated. This effect is known as cymophane effect. If a Chrysoberyl exhibits a thin narrow band of reflecting light across its length which slightly moves when a polished gem is rotated, the effect is known as a cat's eye effect. Cat's eye and cymophane effects are caused by microscopic, parallel, needlelike inclusions that cause the light to reflect distinctly within a stone. Both Cymophane and Cat's Eye are variety names used to described Chrysoberyl with these effects. Other minerals and gemstones may also exhibit cymophane or cat's eye effect, but Cymophane and Cat's Eye when used alone are only describing the Chrysoberyl type. For example, Quartz that exhibits cat's eye is known as Cat's Eye Quartz (or Quartz Cat's Eye), whereas Chrysoberyl Cat's Eye is known simply as Cat's Eye. Alexandrite may also occur in Cat's Eye or Cymophane forms, but this is extremely rare.
For additional information, see the gemstone section on Chrysoberyl, Alexandrite, and Cat's Eye.
Crystal Forms & Aggregates
Other ID Marks
Complex Tests
Striking Features
Environment
Varieties
✓ common · ✗ uncommon
- Alexandrite— Rare variety of Chrysoberyl that exhibits a different color in natural and incandescent light. For more information, see the gemstone section on Alexandrite.
- Cat's Eye— Gem Chrysoberyl that exhibits a cat's eye effect, in that it reflects a long thin wave of light across a polished cabochon gemstone. Although the term Cat's eye can be applied to other gemstones with this name, the Chrysoberyl form is the most well-known. For more information, see the gemstone section on Cat's Eye.
- Cymophane— Polished Chrysoberyl exhibiting a floating light reflection known as a cymophane effect.
- Precious Cat's Eye— Synonym of Cat's Eye.
Uses
Noteworthy Localities
In the U.S., Chrysoberyl has been found in the Gillette Quarry, Haddam, Middlesex Co., Connecticut; Topsham, Sagadahoc Co., Maine; and Greenfield, Saratoga Co., New York; and Golden, Jefferson Co., Colorado. Several classic crystals were found in the early 1900's in the West Side of Manhattan in New York City, New York.
Common Mineral Associations
Distinguishing Similar Minerals
Topaz - Very hard to distinguish without complex tests, though Chrysoberyl is generally paler in color.
Photos
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