“Look, here it is, the prophetic Russian stone! O craft y Siberian. It was always green as hope and only toward evening was it suffused with blood.”
Nikolai Leskov, The Alexandrite, Mysterious Interpretation of a True Fact (1884)
Alexandrite was named by Count Perowskij, who gave this marvelous gemstone its name to honor the future Russian Czar Alexander II (1818-1881), who was given the gemstone on his sixteenth birthday.
Chemical composition of Alexandrite
From a strictly mineralogical perspective, Alexandrite is the most sought-out Chrysoberyl member of the oxide and hydroxide class due to its color change. This peculiar property depends on two factors - the quality of the light source and the way in which it is reflected by chrome. Natural and artificial (incandescent) lights contain different quantities of the color spectrum (blue, green, orange, red, violent and yellow). Chrome absorbs yellow, while white light passes through Alexandrite, splitting into equal parts of blue and green. Sunlight is more well-balanced, containing a greater quantity of the green preferred by our eyes, making Alexandrite appear green in candescent light, while its color shifts towards red in incandescent light (which contains more red).
Russian Alexandrite is certainly the most well-known, but it is no longer available from this market. Together with Russia, Sri Lanka has been the primary source of Alexandrite extraction for a long time. Beautiful examples have also been produced in India, Tanzania and Brazil. Small quantities are sourced from Myanmar, Madagascar, Mozambique and Zimbabwe.
History of Alexandrite
An extremely rare gemstone, Alexandrite was first discovered in the mid 19th century, where it quickly became the foundation for the Soviet jewelry industry. Unfortunately, the original Russian source has dried up, and the only remaining link to its motherland is in its name.
A rare Cat's-Eye Alexandrite
Properties of Alexandrite
In addition to color change, mentioned above, Alexandrite also exhibits another optical property: trichroism, thanks to which the gemstone can display three distinct colors (green, red and yellow) depending on the viewing angle. As a type II gemstone, Alexandrite contains visible inclusions, particularly in stones heavier than one carat, but they do not interfere with its beauty.
Alexandrite and the phenomenom of color-changing
Varieties of Alexandrite
A rare variety of Alexandrite is the Cat’s Eye variety which, thanks to its subtle needle-shaped inclusions of rutile, reflects light in a way that produces an effect similar to a cat’s pupil. This effect is also called ‘chatoyancy,' and occurs with cabochon cut gems with its convex surface.
Care for Alexandrite
Alexandrite may be subjected to steam cleaning, but not ultrasound.