ALEXANDRITE, a variety of chrysoberyl (q.v.) discovered in the Urals in 1833, on the day set apart for celebrating the ma jority of the Russian cesarevich, afterwards the tsar, Alexander II., in whose honour the stone was named. It is remarkable for being strongly dichroic, that is, exhibiting different colours ac cording as viewed from different directions, generally appearing dark green by daylight and raspberry-red by candle-light, or by daylight transmitted through the stone. As red and green were the military colours of Russia, the mineral became highly popular as a gem-stone.