Alexandrite is a phenomenal variety of Chrysoberyl. At its best, Alexandrite has a color change from purplish Red under incandescent light to bluish Green in daylight. Alexandrite is named for Tsar Alexander of Russia, where it was initially discovered. Other sources of Alexandrite are Brazil and Sri Lanka. Alexandrite is one of the birthstone for June and is a well known rare gem. It has a hardness of 8.5 and is an excellent choice for jewelry.