Alexandrite was first discovered in
1830 in a Russian emerald mine in the Urals. On the occasion of Prince Alexander II's
21st birthday, the gem was dedicated to him by the mine's workers.
Alexandrite contains a trace of chromium, making it the most effective at transmitting
green light, second best at transmitting red light, and very effective at absorbing all
other wavelengths. As a result, the stone transmits the most green light during the day,
when it is exposed to sunlight, giving it a green appearance. It also appears blue when
illuminated by an approximately white light, comparable to daylight. However, when
candles, oil lamps, or tungsten filament incandescent lamps with a high red content are
used at night, the stone transmits the most red light, giving it the appearance of being
red. Alexandrite is an excellent treasure due to its striking and obvious color-change.