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The product description goes into detail of how to produce a fake gold bar and how real their product appears, and even emphasizes that it passes common tests f
by daneel_w 4y ago
The product description goes into detail of how to produce a fake gold bar and how real their product appears, and even emphasizes that it passes common tests for authenticity - chemical, weight, resonance and even x-ray. "Our gold-plated tungsten bar and tungsten alloy golden bar are only for souvenir and decoration purpose". But, of course...
- tyingq 4y agoUltrasound testing is probably a weakness. Edit: Sound passes through tungsten and gold at significantly different rates. Also, a "mixed media" type material would have extra "echos" that a homogenous thing would not.
- ajot 4y agoMaybe a Differential Thermal Analysis/Thermomechanical Analysia? I suspect gold and tungsten have different behaviours when heated, and that should tell both apart. https://en.wikipedia.org/wiki/Differential_thermal_analysis https://en.wikipedia.org/wiki/Differential_thermal_analysis https://en.wikipedia.org/wiki/Thermomechanical_analysis https://en.wikipedia.org/wiki/Thermomechanical_analysis
- deleted 4y ago[deleted]
- speakeron 4y agoThey have different magnetic susceptibilities. Gold is diamagnetic (repelled by magnetism); tungsten is paramagnetic (attracted). A strong magnetic field (neodymium magnets) and sensitive scales can tell them apart. I built a small rig a few years ago with parts from Aliexpress that worked for coins and for bars it's just scaling it up.
- ginko 4y agoLooks like tungsten has more than twice the electric resistivity of gold. Setting up a conductivity test shouldn't be too hard.
- daneel_w 4y agoBecause of electrical current preferring the path of least resistance (the gold instead of the tungsten), and because of the Skin effect (https://en.wikipedia.org/wiki/Skin_effect https://en.wikipedia.org/wiki/Skin_effect), I suspect such a test would be inaccurate. Especially given how thick the plating is in these particular bars.
- tyingq 4y agoA high current test might work, albeit with some undesirable side effects :)
- upofadown 4y agoNo skin effect for the direct current you could normally use to measure resistance. Accurately measuring the resistance of something as large as a metal bar can be tricky, but the gold would help as it does not oxidize on the surface.
- marcosdumay 4y agoThe skin effect happens exclusively on alternating currents, and you will need a fairly high frequency for it to become a problem on the size gold bars usually have. So, no, it's completely irrelevant here.
- kube-system 4y agoWho doesn’t run chemical and x-ray fluorescence tests on their knickknacks?
- adrian_b 4y agoTo identify a gold-plated object, those would have to be done in a destructive manner, i.e. after scratching the object. In many cases that would not be acceptable, so non-destructive tests may be used, e.g. based on density or X-ray absorption, but those are inconclusive, because tungsten also passes them. When scratching the object is allowed, then there is little need for a complex test, as the change of color would be enough to show a fake.
- daneel_w 4y agoProduct description tells us that the gold plating is 1/16" thick (~1.6 mm), and that such thick plating of gold is necessary to fool x-ray testing. I don't know how invasive scratch tests are but I imagine the carving to be shallower than 1.6 mm. Their product is clearly and thoroughly designed for counterfeiting.
- gymbeaux 4y agoIt is clearly designed for counterfeiting. If your concern and interests are truly limited to trade shows, I’m sure an ingot of steel painted gold would suffice.
- sandworm101 4y agoIf only they invested as much energy into spellchecking. I expect these come stamped "99.99 per cent gold".
- dvh 4y agoSame as "massage toy" on AliExpress
- varjag 4y ago"solvent trap"