Cat’s Eye

History
Even though the cat’s eye chrysoberyl has a mysterious, some might say sinister, appearance, no myths or superstitions have ever been attached to it. It remained more or less a gemstone collector’s item until the 20th century, when true appreciation for this rare and valuable jewel swiftly developed. Although other gems such as tourmaline, corundum, spinel and quartz may also feature a similar cat’s eye phenomenon, the name “cat’s eye” is reserved only for the finest of all, namely the chrysoberyl cat’s eye. Another term for this fascinating jewel is Cymophane, from wave (kyma) and appearance (phanein) in Greek.

 

Colour
The cat’s eye chrysoberyl colour spectrum is restricted to shades of yellow, green and brown. They sparkle in hues of finch yellow to lime green via deep chartreuse (yellowish-green) and olive green to warm, smoky, golden tobacco tones, as expressed in the words of Dr. Eduard Gubelin.

 

Gemmological Properties
‘Chat’ – the French for cat – already hints at this gem’s exceptionally eye-catching characteristic, namely chatoyancy, the slit-like ray of light running over the gem’s surface resembling a cat’s pupil. When turning the stone, the ray of light dances swiftly across the surface, as if detached from the gem itself. What causes this wonderful phenomenon? Embedded within the crystal are minute parallel fibres of another mineral called rutile, on which light reflects at certain angles. The cabochon cut, with its curved and smooth surface, reveals this bright band of light most efficiently. The narrower and more precise the line of light, the more sought after and valuable the stone.