The mineral called chrysoberyl is a beryllium aluminate with the formula BeAl2O4. The name chrysoberyl is derived from the Greek words χρυσός chrysos and βήρυλλος beryllos, meaning "a golden-white back".
The common chrysoberyl is yellowish-green and transparent to translucent. When the mineral shows a good colour from pale green to yellow and is transparent, then it is used as a gemstone. The three main varieties of chrysoberyl are: ordinary yellow to green chrysoberyl, cat's eye or cymophane and alexandrite. Yellow-green chrysoberyl was called "chrysotile" during the Victorian and Edwardian eras, which caused confusion because that name was also used for the mineral olivine ("peridot" as a gemstone); that name is no longer used in gemological nomenclature.