19c Using Hot Point – Detecting B Jade)
Using a diamond drill bit to grind off an inconspicuous area
Jade dealers often use ‘hot point’ for home detection on whether a jadeite jade has been impregnated with polymer.
Polymers when come into contact with a hot point emits a ‘plastic and resinous’ smell when the resin melts. Natural jadeite jade does not contain organic compounds, so when a small area is touched with a hot point, a Type B jade will give off the characteristic ‘plastic’ smell.
If you have a jadeite jade carving you can use a diamond drill bit to ‘grind’ off a small inconspicuous area. Some jade dealers use a rotary wheel grind stone to polish off a small area. Then he smells for the presence of polymers. The small area can then be re-polished back with a very slight lost in weight.
Hot pointing a jade piece to test for polymer
Alternatively you can use a soldering iron to do the trick. The hot tip of a soldering iron has a temperature of at least 250oC and this is enough to melt the polymers within a jade piece if it is a Type B jade. The nose can pick up the distinctive plastic smell easily.
In fact a number of jade dealers use this crude method for the detection of polymers within a jade piece.
You have to note that both are destructive test. But a jade cutter can re-polish back the affected area to its original luster.
Category: 19c Hot Point – Type B Jadeite Jade
Many thanks, Arthur, for your information on home-detection of ‘B’ jade!
I had no idea that an UNpolished backing to a stone was a good sign.
Again, thank you!