Cymophane

Big Photo

Brazil
1.39 carats
© Mineral Classics

Cymophane has its derivation also from the Greek words meaning 'wave' and 'appearance', in reference to the exhibited chatoyancy. It is the only gem which is simply known as Cat's eye.

Chatoyancy is caused by light reflecting from inclusions of tiny parallel needles or hollow tubes. The finest quality cat's eye should be sharp, intense, well-centered, correctly oriented. Silver-white colour band is preferred. Most-prized bodycolor is semi-transparent golden-yellow to slightly greenish-yellow or brownish yellow "honey" color.

Cat's eye chrysoberyl can exhibit "Opening and Closing" and "Milk and Honey" effects.

Cymophane Gemstones by Colour

This table shows the variety of hues this gemstone can be found in. Click on a photo for more information.
 
 

Cymophane Gemstones by Size

This table shows distribution of Cymophane gemstone sizes that are listed on this site. This can give a good indication as to the general availability of this gemstone in different sizes.
Contributed photos
Lightest:0.77 cts
Heaviest:7.27 cts
Average:1.91 cts
Total photos:10
Do you have a larger Cymophane? Why not upload a photo?
0.77ct to 1.42ct1.42ct to 2.07ct2.07ct to 2.72ct2.72ct to 3.37ct3.37ct to 4.02ct4.02ct to 4.67ct4.67ct to 5.32ct5.32ct to 5.97ct5.97ct to 6.62ct6.62ct to 7.27ct
General Information
A variety or type of:Chrysoberyl
Chemical Formula
BeAl
 
2
O
 
4
Arthur Thomas, Gemstones (2009)
Cymophane Treatments
Irradiation of light variety produces dark (olive)-brown color: may be radioactive. - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 3
Cymophane Simulants
Cat's eye quartz, cat's eye tourmaline, bleached tiger's eye quartz, glass. - GIA 2019
Synthetic Cymophane
In 1987 Japan's Kyocera Corporation created commercially-available synthetic cat's eye color-change alexandrite, which is a rare combination. - GIA 2019
Physical Properties of Cymophane
Mohs Hardness8.5
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Specific Gravity3.69 to 3.81
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Optical Properties of Cymophane
Refractive Index1.739 to 1.770+
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Optical CharacterBiaxial/+,-
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Birefringence0.007 to 0.013
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
ChatoyancyBluish (or yellowish according to other sources) chatoyancy
Gemdat.org, Management Team (2012)
Colour
Colour (General)Yellow, green
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
TransparencyTransparent,Translucent
Michael O’Donoghue, Gems, Sixth Edition (2006)
LustreVitreous
Michael O’Donoghue, Gems, Sixth Edition (2006)
Crystallography of Cymophane
Crystal SystemOrthorhombic
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Inclusions in Cymophane
Microscopic tube-like cavities or needle-like inclusions of rutile in an orientation parallel to the c-axis - mindat.org
Further Information
Mineral information:Cymophane information at mindat.org
Significant Gem Localities
Sri Lanka
 
  • Sabaragamuwa Province
    • Ratnapura District
      • Ratnapura
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