Alexandrite

About Alexandrite

One of the rarest and most expensive gemstones - fine quality can exceed $70,000 per carat. Discovered in Russias Ural Mountains in 1830 and named after Tsar Alexander II. It exhibits dramatic color change: green or blue-green in daylight, red or purplish-red under incandescent light. The effect is caused by chromium ions that absorb different wavelengths of light. Russian sources are nearly exhausted. Sri Lankan and Brazilian material exists but rarely shows the vivid color change of Russian stones. It is sometimes called an emerald by day, ruby by night. Synthetic alexandrite exists but the natural stones remain extraordinarily valuable.