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Using Hot Point – Detecting B Jade

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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.

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I am a Graduate Gemologist trained at the Gemological Institute of America (GIA) in New York City, USA. I hold an MBA degree from Cranfield University, United Kingdom, and a Bachelor degree in Mathematics. My earlier profession was a banker until I found jade in Myanmar (Burma) in the early 90s. I have traveled to the fabled Hpakan Jade mines, and Mogok, the world’s famous rubies and sapphires mines in upper Burma, with my second son. Three of my children are also Graduate Gemologist, GIA, NYC and they deal in diamonds, gemstones and jade. 我是在美国纽约市的美国宝石学院(GIA)接受过培训的宝石研究学家。 我拥有英国克兰菲尔德大学的工商管理硕士学位和数学学士学位。我以前的职业是银行家,直到90年代初我在缅甸接触到玉石。我曾经和我的次子一起去过缅甸上流传说中的哈帕翡翠矿山和莫谷矿山, 莫谷矿山是世界上著名的红宝石和蓝宝石矿山。我的三个孩子都是纽约市GIA毕业的宝石研究学家, 他们专门处理钻石,宝石和玉石.

1 COMMENT

  1. 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!

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