Alexandrite is the color-changing variety of the mineral species chrysoberyl.
It is one of the birthstones for June. Alexandrite is said to enable its wearer to foresee danger.
The most sought after alexandrites are a lovely green in daylight or fluorescent light, but change to red or slightly purplish red in the incandescent light from a lamp or candle flame.
Abundant alexandrite deposits were first discovered in 1830, in Russia’s Ural Mountains.
Those first alexandrites were of very fine quality, and displayed vivid hues and dramatic color changes.
The gem was named after the young Czar Alexander II, and it caught the country’s attention because its red and green colors mirrored the Imperial Russian flag.
Now most alexandrite comes from Sri Lanka, Brazil, India, Tanzania, and Madagascar.
The newer deposits contain some fine-quality stones, but many possess less precise color change and muddier hues than the nineteenth century Russian alexandrites.
Alexandrite has a hardness of 8.5 on the Moh’s hardness scale, and has excellent toughness.
Alexandrites are typically transparent and at times some of them may contain fingerprint and silk inclusions.
Alexandrites typically come in sizes from tiny to 5 carats. Larger stones are rare.