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32 Cards in this Set
- Front
- Back
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Define: True jade |
Only jadeite & nephrite |
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Define: Hemi jade |
Rocks with a mixture of nephrite and other materials |
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Define: Pseudojade |
No jade component, mistaken as jade |
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Nephrite chemical composition |
Hydrous calcium magnesium silicate with replacements of mg by fe |
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Nephrite How is it formed? |
Metamorphic rock from pre existing magnesium rich rock modified under high heat and temperature |
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Nephrite tity structure |
Compact interlocking fibrous crystals |
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Nephrite crystal system |
Monoclinic |
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Nephrite hardness |
6.5 |
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Nephrite SG |
2.8-3.1 |
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Nephrite lustre |
Waxy vitreous |
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Nephrite transparency |
Translucent opaque |
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Nephrite RI |
1.62 spot |
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Nephrite inclusions |
Black minerals common |
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Nephrite fracture |
Hackly uneven |
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Jadeite chemical composition |
Composed of sodium aluminum silicate from pyroxene group NaAl(Si2O3)2 |
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Jadeite How is it formed |
Formed by metamorphism of pre existing rocks under high pressure moderate temperature |
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Jadeite structure |
Granular structure of interlocking crystals |
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Jadeite crystal system |
Monoclinic |
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Jadeite hardness |
7 varies with grain |
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Jadeite SG |
3.3-3.36 |
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Jadeite lustre |
Virreous greasy |
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Jadeite fracture |
Uneven |
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Jadeite transparency |
Translucent opaque |
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Jadeite ri |
1.64-1.68 spot |
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Identification of Jade |
Hardness test Sg ri Spectrum green under chelsea |
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Jade enhancements |
A jade: bleaching with mild acid followed by light waxing |
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Jade enhancements |
B jade: bleached with strong acids and impregnted with colourless polymer |
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Jade enhancements |
C jade: dyed with blue and yellow aniline dyes or chromium salts |
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Jade enhancements |
B+C jade: bleached then dyed |
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Identification of jade enhancements |
Microscope check for dye in cracks Wax can be drawn out with hot pick Grain boundaries may be enhanced Scratched or damaged surface dye may be detected jn fractures Chelsea filter orange red colour May show colour concentration |
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Jade composites |
Check for closed back jewellery items Coatings may be applied to backs |
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Jade simulants |
-hydrogrossuler garnet -saussurire -bowenite, serpentine -steatite, soapstone -aventurine, quartz -chalcedony, quartz -amazonite, feldspar, microclime -green glass -dyed marble |
