The mineral chrysoberyl is found in transparent yellow to greenish yellow color, but two other varieties are widely known as gemstones: cat's eye and alexandrite.
The variety of chrysoberyl containing rutile needles or negative crystals oriented in the same direction showing some exceptional and sharp chatoyancy is called cat's eye. This optical phenomenon produces the appearance of the likeness of a cat's contracted pupil in the stone.
Chatoyancy may occur in any color of the chrysoberyl but the most highly prized is the slightly greenish yellow or brownish yellow, a color similar to honey.
The other factor affecting the value of the stone is the strength and sharpness of the eye.
When a good quality cat's eye is held toward a concentrated light source, the half of the stone closest to the light will show the body color and the other half will appear quite milky. When the stone is rotated, the colors switch.
Assuming that the stone has a honey colored body, the resultant appearance is often referred as a « milk and honey » effect.
In the Orient, cat's eye is highly revered as a preserver of good fortune, the belief being that it guards the owner's wealth and it protects him from poverty.
In Sri Lanka cat's eye was considered to be a potent charm against evil spirits.