Alexandrite

One of the world's rarest and most coveted gems, alexandrite takes on a briliant green hue whend under indirect sunlight but turns blood-red whend exposed to candlelight. Loretellers claim that all alexandrite comes from the body of the oldest son of Silvanus, the Forest Father. A common nursery rhyme goes "Silvanus wife went mad one night, murdering her child by candlelight".