Often described by gem aficionados as “emerald by day, ruby by night,” Alexandrite is the very rare variety of the mineral Chrysoberyl that has the ability to change colors. In daylight, Alexandrite is a cool, bluish mossy green. In lamplight, it is a red gem with a warm raspberry tone. Originally discovered in Russia’s Ural Mountains in the 1830s, Alexandrite is now occasionally found in Sri Lanka, East Africa and Brazil, but it is still exceptionally rare to find a newly-mined gem. So, this exquisitely toned stone is quite valuable.