Among the gemstones that display special optical phenomena, cat’s eye gems are particularly interesting, in part because the effect is found in so many different gem varieties. The technical term for the cat’s eye effect is chatoyancy, derived from the French for eye of the cat (“oeil de chat”).
The chatoyant effect resembles, appropriately enough, the slit eye of a cat. The effect is caused by the reflection of light by parallel fibers, needles or channels in the gemstone. Usually the gemstone needs to be cut cabochon style for this effect to be displayed. When the gem is rotated, the cat’s eye appears to glide over the surface.
Chrysoberyl cat’s eye belongs to the same family as the rare alexandrite. Since chrysoberyl is a very hard stone (8.5 on the Mohs scale), it is suitable for all kinds of jewellery. Chrysoberyl cat’s eye is found in Sri Lanka and Brazil, with additional deposits in India, China and Zimbabwe.
|Gold to brown to green and pink||The technical term for the cat’s eye effect is chatoyancy. Chrysoberyl is a very hard stone (8.5 on the Mohs scale).|