What I really need is some suggestion on how to get about polishing jade -jadeite/nephrite and how to grade or to distinguish between natural and treated.
Hi Chris,
Jadeite and nephrite jade are both porous. The grey and white
varieties are often dyed into a fine green colour by an organic
dye to enhance their appearance. A microscopic examination will
normally show that the colour is concentrated along the veins of
the stone, it will show intense very small spots of colour within
the polycrystalline structure.
The dyed green material will show pinkish under the Chelsea
filter. Natural jade is inert.
Natural green jades have a diagnostic spectrum at 437nm. Dyed
green materials will show two broad absorption bands in the red
which is absent in the natural green jades. Dyed jades have no
absorption band at 437nm.
Stained green jades is prone to fade in strong light.
A stained mauve jadeite is also produced, those stones do not
fade. Their colour is more intense than the natural material and
look unreal.Those stones may have an orange fluorescence.
Best regards,
Francoise.