Real jade
Two minerals, three grades, many imitations.
What jade actually is, what the A, B and C grades mean, the stones and glass sold as look-alikes, and why only a lab can tell you for sure.
What jade is
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Jade is more than one mineral
Jade isn't a single mineral. Gemologists use the word for jadeite and nephrite, and under certain conditions for a green mineral called omphacite.
Source: GIA Gem Encyclopedia, Jade
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Hardness of jadeite and nephrite
GIA lists hardness ranges of 6.5 to 7 and 6.0 to 6.5 on the Mohs scale, in the order it lists jadeite and nephrite.
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Where jadeite is found
Gem jadeite has known sources in Myanmar, Japan, Russia and Guatemala, and Myanmar still dominates the market.
Source: GIA Gems & Gemology, Guatemalan Jadeite Jade: Rough and Finished
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Where green nephrite is found
The most economically important sources of green nephrite are northwestern China, British Columbia in Canada, and Siberia in Russia.
The grades
A jade: Natural
Jadeite that's natural or polished with wax only.
B jade: Bleached and filled
Bleached with acid, then filled with polymer resin.
C jade: Dyed
Colored with dye.
Source: GIA FAQ, What is B jade?. GIA notes this system is used in China.
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B jade needs a lab to confirm
The polymer filling in B jade is easier to detect than bleaching alone, but it takes a qualified gemological lab using magnification and advanced analytical techniques.
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Care for bleached and polymer-filled jadeite
AGTA's industry manual says bleaching plus polymer impregnation is common in jadeite and calls for special care: keep it away from heat, chemicals and ultrasonic cleaners.
Source: AGTA Gemstone Information Manual, 17th ed., Gemstone Information Chart
Watch for
Imitations and misleading names
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Some jade names aren't jade
Watch the trade name. GIA says terms like pink jade, Mexican jade and Transvaal jade generally refer to other minerals.
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Serpentine is a common jade imitation
Serpentine, which ranges from yellowish green to deep green, is commonly used to imitate jadeite or nephrite.
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Dyed quartzite imitates jadeite
GIA's Lab Notes have documented many cases of dyed quartzite imitating jadeite, as well as ruby, lapis lazuli and sugilite.
Source: GIA Gems & Gemology, Lab Notes
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Glass bangles sold as jade look-alikes
GIA's lab identified two bangles that resembled nephrite and jadeite as manmade glass, and it notes that jade imitations commonly turn up on the market.