Rare natural color change Alexandrite (.10ct, SI, Cylon) hand set in solid 925 sterling silver weeping heart on a 925 sterling silver chain. Color change Alexandrite is one of the 10 rarest gemstones. Named for Csar Alexander of Russia, said to have been discovered on the Casr's birthday. The gem changes from green in sun light to purple in incandescent light. (Please make sure it's one or the other as mixed light and fluorescent lighting doesn't work)