CATS EYE

Cat’s eye is basically Chrysoberyl gemmologically. It occurs in a range of colours from green to yellow to brown. It is a hard and durable stone. This stone when cut en-cabochon, has a near whit line across the stone and gives the effect of a cat’s eye ,hence the name. This effect is due to canal or feather like fluid inclusions, or needle like inclusions of rutile. The highly prized colour for this is light golden brown often with a shadow that gives a light and dark'milk and Honey’ effect. It is mainly Beryllium aluminium Oxide with a formula BeAl2O4. The best stone is found in Urals in mica schists.Sri lanka,Burma,Brazil,Zimbabwe, China also produce Cat’s eye.
The hardness of this stone is 8.5,specific gravity 3.71,refractive index 1.74-1.75 and Orthorhombic crystal structure.
Cat’s eye is the precious stone for Ketu. The semi precious substitute for this is Alexandrite.
Alexandrite is also chrysoberyl with the same composition as cat’s eye and the same physical properties described above. The very rare and valuable Alexandrite changes from green in daylight to red,mauve,or brown under incandescent light. It is best when it is transparent and differs only that when cut ,it does not produce the effect of a white line across it.