Cymophane

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Physical & Optical Properties

Category Semi-Precious Gems

Mohs Hardness 8,5

Specific Gravity 3,69 – 3,81

Refractive Index 1,739 – 1,77

Crystal System Orthorhombic

Luster Vitreous

Color various

Birefringence 0,007

Mohs Hardness

Mohs hardness of Cymophane shown against the ten reference minerals, from talc (1) to diamond (10).

Mohs	Reference mineral	Cymophane
1	Talc
2	Gypsum
3	Calcite
4	Fluorite
5	Apatite
6	Orthoclase
7	Quartz
8	Topaz
9	Corundum
10	Diamond

Crystal System

Value & Market

Price Tier Fine ($500-5,000/ct)

Where to Buy Cymophane

Blue Nile Fine jewelry retailer

James Allen Gemstone jewelry

Brilliant Earth Ethically sourced gems

Amazon Wide selection

Links may earn a commission at no extra cost to you.

Treatments

Irradiation of light variety produces dark (olive)-brown color: may be radioactive. - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 3 Cat's eye quartz, cat's eye tourmaline, bleached tiger's eye quartz, glass. - GIA 2019 In 1987 Japan's Kyocera Corporation created commercially-available synthetic cat's eye color-change alexandrite, which is a rare combination. - GIA 2019 8.5Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) 3.69 to 3.81Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) 1.739 to 1.770+Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) Biaxial/+,-Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) 0.007 to 0.013Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) Bluish (or yellowish according to other sources) chatoyancyGemdat.org, Management Team (2012) Yellow, greenHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) Transparent,TranslucentMichael O?Donoghue, Gems, Sixth Edition (2006) VitreousMichael O?Donoghue, Gems, Sixth Edition (2006) OrthorhombicHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) Microscopic tube-like cavities or needle-like inclusions of rutile in an orientation parallel to the c-axis - mindat.org Cymophane information at mindat.org Sri Lanka 

About Cymophane

Cymophane is the chatoyant variety of chrysoberyl, more commonly known as cat's eye chrysoberyl, displaying a sharp, milky-white luminous line that glides across its domed surface like the slit pupil of a cat's eye—the finest example of the chatoyancy optical phenomenon in gemology. When a gem dealer says 'cat's eye' without qualification, they always mean cymophane. The finest stones come from Sri Lanka and show a bright eye on a honey-yellow to greenish background.

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