Alexandrite is a color-change variety of chrysoberyl that appears as different colors under daylight and incandescent illumination. Pictured here is a faceted specimen of color-change alexandrite of 26.75 carats from Tanzania, showing a blue-green color in daylight and a purple-red color under incandescent light. Natural alexandrite of good color and clarity is an extremely expensive gem, however, lab-created alexandrite can be found in many jewelry stores. Some of the lab-grown alexandrite has a spectacular appearance!