The mineral or gemstone chrysoberyl, not to be confuse with beryl, is an aluminate of beryllium with the formula BeAl2O4. The name chrysoberyl is derived from the Greek words chrysos and beryllos, meaning "a gold-white spar". Despite the similarity of their names, chrysoberyl and beryl are two completely different gemstones. Chrysoberyl is the fourth-hardest natural gemstone and lies between corundum and topaz on the hardness scale. Chrysoberyl is a mineral consisting of ordinary colorless or yellow transparent chrysoberyl, cymophane (chrysoberyl cat's eye), and alexandrite.