alexandrite
Alexandrite from Sri-Lanka red under incandescent light
Alexandrite from Sri-Lanka red under incandescent light
twinned alexandrite crystalform Novello in Rhodesia – natural light
twinned crystal of alexandrite from Novello Rhodezie under incandescent light
twinned crystal of alexandrite from Ural in Russia
alexandrite from Sri Lanka trillion cut
cloud like liquid inclusions
inclusions in pink alexandrite
inclusions in green alexandrite
Detailed sheet
alexandrite
It is the rariest chrysoberyl variety, named after the future Czar Alexander II because it was discovered in the Ural in 1830, on the day he came of age and because of its 2 colors : green and red were the colors of old Imperialist Russia.
Also called the “cameleon stone” or “Emerald by day, Ruby by night”.
The color change is displayed dependent upon the nature of ambient lighting : green sometimes bluish by daylight and purplish red (raspberry red for the rariest and the most beautiful) by incandescent light. This is a unique and misterious gemme, une true curiosity. This changing color is best seen in thick stones. This variation in the color depends on the gemme’s origine and to the chromium content in its crystal structure.
Only diamond and corundums (ruby, sapphire) have a higher hardness, which make alexandrite an ideal gem for jewelry use. The “cat’s eye”, a variety displaying chatoyancy due to inclusions is also very valuable. Can be confused with the changing color grenats.
CHEMICAL CHARACTERISTICS
BeAl2O4
beryllium aluminium oxide
PHYSICAL CHARACTERISTICS
Main color
green
Other colors
red
extraordinary color change: it is green in daylight and purpulish red in artificial incandescent light
Color of streak
white
Luster
vitreous
Hardness
8.5 to 0.0
Density
3.71 to 3.74
Cleavage
indistinct
Fracture
conchoidal, uneven
OPTICAL PROPERTIES
Transparency
transparent
Refractive index
1.745 - 1.755
Double refraction
0.009
very weak, anisotropic, biaxial (+)
visible double refraction
No
Dispersion
0.015(0.010)
Pleochroism
definite
Number of colors
3
natural daylight : green, red, yellow. Incandescent light : dark green, orangish red, dark red
Absorption spectrum
680 - 655 - 640 - 555
variable according to the stone orientation, here green
spectrum system alexandrite alpha
spectrum system alexandrite gamma
Fluorescence
weak
red
Inclusions
macle, thin rangy and parrallel channels.
CRYSTALS PROPERTIES
thick prisme, contact and penetration twins common, often repeated forming rosette structures, such as chrysoberyls
crystals system
orthorhombic
OTHER INFORMATIONS
Astrological sign
Aquarius, Cancer, Sagittarius, Virgo
Month
june
APPROACHING GEMS
Exploited
sites
The most beautiful alexandrites were mined in Russia in a deposit in Ural, long the Takovaïa river which also produced emeralds but those deposits are worked out. Today beautiful crystals are found in Sri Lanka where a big crystal has been extracted in 1876 in Zimbabwe, Brazil, Burma, USA, India, Madagascar, Tanzania, Tasmania.
use in jewelry
Clean and light are faceted, the one with inclusions are cut into cabochons.
This is one of the most valuable gemstones currently, high-quality alexandrite with a very neat color change are rare and very expensive. The Russian alexandrites are considered as the one displaying the best change of color.
The price of beautiful alexandrites, clean with a beautiful color change can as high as diamond of the equivalent size.
“cat’s eye” cabochons with a color change are also very valuable with a very high price when over 4 cts.
Alexandrite is the 55th wedding anniversary stone.
Daily care
and precautions
Quite tough and easy to care. Resistant to heat and acids.
imitations and
treatments
Synthetic alexandrite exists since 1972 but it is expensive to produce. However many imitations are synthetic corundums, synthetic spinels. Also imitated with doublets with garnet table and green glass pavillon. Synthetic alexandrites and synthetic corundums are strongly fluorescent in red. Most of the alexandrite imitations are synthetic corundums.
Historical
healing properties
It would be the stone of the balance between the strength and the justice, the power and the humility, the aggressiveness and the sweetness. It would be suitable for politicians, businessmen…garanting them success while avoiding mistakes.
Its balance role would act on the energy circulation between the coronal chakra and the root chakra.
It would balance both mental and physic building a serenity mood promoting harmonious relationships.
Other
Gems
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