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Fakes & FraudsFake Chinese 'Turquoise'

28th Apr 2015 19:44 UTCSteve Hardinger 🌟 Expert

I have a fake Chinese 'turquiose' nugget with specific gravity = 2.42. This seems a bit low for the two speciesI recall that been dyed to produce this material: magnesite (sg = 2.98-3.02) and howlite (sg = 2.53-2.59). I have faith in my sg measurement because the same scale gave good experimental sg values for tourmaline, kunzite, and beryl.

Any suggestions other than howlite and magnesite? No chemical tests have been done yet because I need to complete photography of the nuggets in tact before breaking it open.

28th Apr 2015 20:43 UTCOwen Melfyn Lewis

Hi Steve,

Could be 'reconstructed' turquoise, that is turquoise dust mixed with a polymer resin binder and pressed into blocks before being cut and re-worked. Take a look here http://www.gemsdat.be/turquoise.htm under Tables second section from the top of the page.

If you are going to get destructive with a piece in due course, expose a crumb of it to a gas flame. If reconstructed' it will smoke, smell etc. I keep a small butane hand-torch (of the sort sold in kitchenware shops for caramelising the tops of creme brulee etc.) for exactly this purpose.

28th Apr 2015 22:31 UTCSteve Hardinger 🌟 Expert

I haven't performed any destructive testing yet. I can say that the heft feels too heavy, and the color is too homogenous (IMHO) for this to be 'stabilized turquoise'. I'm looking forward to breaking it open in the near future.

28th Apr 2015 23:02 UTCOwen Melfyn Lewis

'Stabilised' and 'reconstructed' are two very different things. Check it out.

29th Apr 2015 22:10 UTCGary Weinstein

They also dye coliform aragonite to resemble Turquoise. Inside will be white.

Gary