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Chrysoberyl Gemstone Information

The name Chrysoberyl is derived from the Greek words 'Chrysos' & 'Berullos' meaning 'Golden Crystal'. Although the name refers to the golden yellow colour, it also occurs in a lighter yellow and shades of green and brown.

Chatoyant material is cut as a cabochon (en-cabochon) to display a fine cat's eye effect. The term Cat's Eye, without reference to a particular gemstone name, is used to indicate that the gemstone is a chrysoberyl. Other cat's eye gemstones are named, for example, cat's eye quartz, cat's eye tourmaline etc.

Cat's eye is the most precious of all chatoyant gemstones, it has a sharper eye than that of other chatoyant stones. The inclusions that cause the eye effect are very fine oriented needles of rutile or other minerals.

Alexandrite is a rare colour change variety of chrysoberyl, follow the link for details.

Physical Properties

Stone type:
Chrysoberyl.
Crystal System:
Orthorhombic.
Chemical Composition:
Beryllium Aluminium Oxide, BeAl2O4.
Colour:
Yellow, golden yellow, green and brown. Alexandrite is a colour change stone, showing green in sunlight (daylight) and red in incandescent light and candle light.
Lustre:
Bright vitreous.
Pleochroism:
Trichroic, strong in dark stones, weak in light stones.
Dispersion:
Low.
Hardness:
8 1/2 on the Mohs' scale of hardness.
Toughness:
Excellent.
Cleavage:
Indistinct.
Density in gm/cc:
3.70 to3.78
Double refraction:
Yes.
Refractive index:
1.74 to 1.76

Common Treatments

Chrysoberyl is not normally treated, but cat's eye is often imitated by cat's eye quartz and other chatoyant materials.


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