The extremely rare colour-change gem Alexandrite is a Chromium rich variety of Chrysoberyl. Despite the naming similarity, and the presence of Beryllium, it is not a variety of the more commonly known Beryl crystal, who's colour variants include Aquamarine, Emerald and Morganite. It has a very high specific gravity, making it an extremely heavy crystal for its size. Chatoyant Chrysoberyl is the gemstone which is most commonly given the name of Cat's Eye, due to the presence of tiny fibres within the crystal.
| Alternative Names | Cats Eye |
| Colour | Yellow, Green, Brown, Red |
| Hardness | 8.5 |
| Crystal system | Orthorhombic |
| Streak | White |
| Lustre | Vitreous |
| Main Locations | Russia, Brazil, Australia, Madagascar, Sri Lanka |
| Chakra | Solar Plexus |
| Zodiac | Gemini, Leo |
| Numerology | 6 |
| Planetary | N/A |
| Element | Air, Water |
