Alexandrite | Gemopedia


Alexandrite is the rare, phenomenal, color-change variety of the chrysoberyl mineral, along with its cousins yellowish transparent chrysoberyl and chatoyant or cat's-eye chrysoberyl. Alexandrite's rarity is a result of its chemical makeup; alexandrite can only form when aluminum and beryllium combine with trace elements like iron, titanium and, most importantly, chromium--which causes alexandrite's color change and is very rarely found in nature. The unlikelihood of the rare element chromium being in the right place to combine with aluminum and beryllium under exactly the right conditions to create alexandrite is what makes it so rare and valuable.


At 8.5 on Mohs' hardness scale, alexandrite is hard, tough, and durable enough for daily wear. It requires no special or unusual care, so you're safe to wear and enjoy it freely.


Alexandrite is green or bluish-green in daylight, changing to raspberry red or purplish-red in incandescent light. Alexandrite can also appear in yellowish-, brownish-, or grayish-green shades in daylight, with an orangish- or brownish-red counterpart in incandescent light. Because of its color change, alexandrite has sometimes been referred to as emerald by day and ruby by night.





Cats Eye







While nearly all gem alexandrites are beautiful stones, the value of fine alexandrite is closely tied to the strength of each stone's color change. Like most other colored stones, alexandrite's value is also determined by its color (the degree of saturation) and its clarity, though as a type II gemstone, alexandrite is expected to show some inclusions to the unaided eye that don't detract much from its beauty. Supply/availability and rarity also figures strongly on rare alexandrite's value. Alexandrite only forms when aluminum/beryllium and chrome (which rarely occurs in nature) come together, accounting for its rarity.

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Discovery and Name Origin/Meaning

Alexandrite was named in honor of Russian Czar Alexander II because it was rumored to have been discovered on his birthday in 1834, though that history is debated. While alexandrite might not have been discovered on Czar Alexander's birthday, because it was discovered in Russia and because it does change from green to red--the two colors of the Russian flag--naming the stone after Alexander was still a reasonable decision. Alexandrite was discovered in the Ural Mountains of Russia in the 1830s, though probably not on Czar Alexander II's birthday and probably not by the Finnish mineralogist credited with it. The first name proposed for alexandrite was "diaphanite," a combination of the two Greek words di meaning "two" and phan, which means "to appear."


When chromium oxide replaces some aluminum in alexandrite, the stone's famous and beloved color change is possible. In addition to the characteristic green-to-red color change (from daylight to incandescent light), some alexandrite can change from yellowish or pink to raspberry red. In addition to the color change that alexandrite is known for, not many gem enthusiasts know that alexandrite can also exhibit the phenomenon of chatoyancy or the "cat's-eye effect." While cat's-eye chrysoberyl is well known and highly sought after, the gem variety alexandrite itself can also exhibit a cat's-eye effect when cut en cabochon. When the term "cat's-eye" is used alone, it refers only to chatoyant chrysoberyl, not chatoyant alexandrite or any other cat's-eye gemstone.

The Smithsonian Institution houses the world's largest known Russian faceted alexandrite, a beauty weighing 66 carats. The crystal reported to be the largest gem-quality alexandrite ever found is the Sauer Alexandrite, a 122,400-carat uncut crystal that was found in Bahia, Brazil, in 1967.

alexandrite facts

Because alexandrite is known for its strong color-change ability, other color-change stones (like some garnet and spinel) are said to have "the alexandrite effect."

Alexandrite is an alternative birthstone for June.


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