The name Chrysoberyl is derived from the Greek words chrysos and berullos, meaning “golden” and “gem crystal.” Despite the similarity of their names, Chrysoberyl and Beryl are two completely different gemstones unrelated in any other way. Members of the beryl group include emerald, aquamarine, and morganite while members of the chrysoberyl group only include chrysoberyl, cymaphane and alexandrite. Beryl is a silicate with chemical composition Be3Al2(SiO3)6 and chrysoberyl is an oxide with composition BeAl2O4. Although they both contain beryllium, they are separate gemstone species and do not crystallize the same. Beryl crystallizes hexagonally while chrysoberyl crystallizes with orthorhombic arrangements.
With a hardness of 8.5 on Moh's scale, chrysoberyl is extremely hard and third only to corundum (9.0), and diamond (10) in hardness. Faceted chrysoberyl is a beautiful gem which is not well known in its own right. For such a hard and durable material, chrysoberyl is relatively obscure and the undervalued prices don’t seem to reflect its’ ultility as a gemstone.
Chrysoberyl is normally yellow, yellow-green stone or brownish with its color being caused by the presence of iron. Spectroscopic analysis will usually reveal a strong band where the violet takes over from the blue. As the color darkens from bright yellowish-green to golden-yellow to brown, this band increases in strength. When the stone has a strong color two additional bands can be seen in the green-blue. The most common inclusions are liquid-filled cavities containing three-phase inclusions. Stepped twin planes may be apparent in some cases. Some very rare minty bluish-green chrysoberyls from Tanzania owe their color to the presence of Vanadium. These stones are very rare and can command prices as high as alexandrite.
Translucent yellowish chatoyant chrysoberyl is called cymophane or cat's eye. Its name is derived from the Greek words cyma and phanes, meaning “wave” and “appearance.” Microscopic needle-like inclusions inside the stone reflect a streak of light known as the cat’s eye.
Chrysoberyl is a gemstone that is believed to protect its wearer and keep disaster at bay. The cat's eye variety is seen as a particularly effective talisman. Because of its golden tones, chrysoberyl is often associated with wealth. Maybe for luck, it is well known that croupiers often wear crysoberyl cat’s eye rings. The sublte colors and the high degree of hardness make cat’s eyes ideal for gents rings.
Chrysoberyls are said to promote concentration and the ability to learn and to enable the wearer to think clearly. Negative thoughts are said to be transformed into positive energy. Chrysoberyl is also regarded as a gemstone that promotes tolerance and harmony and is associated with the zodiac sign of Leo.