The name chrysoberyl comes from the Greek words chrysos, meaning golden, and beryllos, which refers to its beryllium content. Chrysoberyl has been a prized stone for thousands of years in Asia, as it is believed to provide the wearer with protection from the evil eye. There are three different gem varieties of chrysoberyl. Each of these stones is chemically alike, but optically very different, each one having a unique and beautiful feature of its own. The pale yellow green variety of chrysoberyl came from Brazil, and was known as chrysolite. It was popular in Spanish and Portugese jewelry in the 18th and 19th centuries. This stone displays an exceptional brilliance. Chrysoberyl is the third-hardest frequently encountered natural gemstone and lies at 8.5 on the hardness scale, between corundum and topaz.
Like the eye of a sleek feline predator, the chrysoberyl cat's eye winks at the astonished observer – a real miracle of Nature! That's why only this attractive gemstone has the right to the short, fitting name of "cat's eye". This gem is really something special with its narrow, bright band of light on a shimmering golden background, which seems to glide magically across the surface when the stone is moved.
Often, the name chrysoberyl is spoken in the same breath as that of the beryl group, the most well known representatives of which include the emerald and the aquamarine. The name 'chrysoberyl' comes from the Greek and means 'gold-coloured beryl'. In spite of its name, however, it is not actually a beryl at all. Together with alexandrite, chrysoberyl forms an independent gemstone category, in which the former, which appears to change its colour, is regarded as the more attractive representative, though in fact it is quite definitely the chrysoberyl cat's eye which is entitled to stake that claim.
From a mineralogical point of view, chrysoberyls are aluminium oxide containing beryllium, and thus actually have little in common with the beryls, which belong to the silicate family. Indeed, with their excellent hardness of 8.5 on the Mohs scale, they are clearly superior to the beryls. The popular chrysoberyls come in many nuances between lemon and greenish yellow, and in honey colours and shades from mint green to brownish green, and are mostly found in the gemstone deposits of Brazil, Sri Lanka or East Africa.
Alexandrite’s color change is caused by small amounts of iron or chromium. Alexandrite is also strongly pleochroic, appearing green, red, orange or yellow when viewed from different directions. Cat’s eye on the other hand, displays no pleochroism. The stone ranges in color from a honey yellow or honey brown color, to a yellowish green or almost emerald green. The most highly prized cat’s eye color however, is a light golden brown. Cat’s eye has a lovely velvety, silk like texture and is different than the common quartz variety of cat’s eye, which is brown and called tiger’s eye. Tiger’s eye is much weaker in color than cat’s eye.