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<p>[QUOTE="ToughCOINS, post: 2272957, member: 20480"]@ Bullibags . . . Be careful with your assumptions . . . yes, an ultrasonic tester will differentiate between gold and tungsten of the same geometry. That is because the tester is measuring the fundamental natural frequency of vibration of the tested piece of metal (a function of both mass and stiffness). The test is beneficial for non-destructive testing for tungsten because the densities of tungsten and gold are virtually identical, but their stiffnesses are not.</p><p><br /></p><p>This test method cannot necessarily be relied upon to identify other combinations of metals intended to mimic the density of gold however, as metals both heavier and lighter than gold could conceivably be sandwiched together to produce the desired result. With time and inclination, I'm pretty certain a very deceptive gold-plated sandwich metal could be developed. To detect that, a different test may become necessary.[/QUOTE]</p><p><br /></p>
[QUOTE="ToughCOINS, post: 2272957, member: 20480"]@ Bullibags . . . Be careful with your assumptions . . . yes, an ultrasonic tester will differentiate between gold and tungsten of the same geometry. That is because the tester is measuring the fundamental natural frequency of vibration of the tested piece of metal (a function of both mass and stiffness). The test is beneficial for non-destructive testing for tungsten because the densities of tungsten and gold are virtually identical, but their stiffnesses are not. This test method cannot necessarily be relied upon to identify other combinations of metals intended to mimic the density of gold however, as metals both heavier and lighter than gold could conceivably be sandwiched together to produce the desired result. With time and inclination, I'm pretty certain a very deceptive gold-plated sandwich metal could be developed. To detect that, a different test may become necessary.[/QUOTE]
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