Posted on 10/30/2017 2:01:49 PM PDT by Leaning Right
The Royal Canadian Mint is investigating how a sealed, "pure gold" wafer with proper mint stampings may in fact be a fake.
The one-ounce gold piece, which was supposed to be 99.99 per cent pure, was purchased by an Ottawa jeweller on Oct. 18 at a Royal Bank of Canada branch. Yet tests of the bar show it may contain no gold at all.
(Excerpt) Read more at cbc.ca ...
Gold conducts electricity much better than does tungsten. So I believe that an electrical conductivity test could tell the difference between gold and gold-plated tungsten.
Rug roh
scary
that is probably what is REALLY in the Federal Reserve vaults.
But as long as nobody knows, I guess it doesn’t matter if the tell a(nother) lie.
Sounds legit.
Don’t know what type of measuring set-up you’re thinking of, but if there’s a few microns of real gold all around it will probably pass the conductivity test at low amperage/low voltage (”low” meaning well below kilo Volts and kilo Amps).
Gold conducts electricity much better than does tungsten. So I believe that an electrical conductivity test could tell the difference between gold and gold-plated tungsten.
That likely wouldn't help either, as the outside would be actual gold, which will conduct the electricty as expected.
If the fakes went only to people who buy to store the gold it could go on forever. Somehow this bar went to a Jeweler who would actually use it. If fake gold starts turning up in hoards this could get bad.
There are other simple tests. Pure gold is (very) soft, tungstene is hard, the difference can be felt and heard when choking the bar. Thermal conductivity differ too => heat at one end and observe the difference in the temperature rise rate at the other end). Thermal capacity differ also => put in boiling water or in ice and measure the time it takes to get back to temperature.
Doubt it. The electrons almost all travel on the surface of a conductor, not through the core.
My DIY pinpointer tests the inductive properties of the coin without touching it. Tungsten and gold are way far apart on frequencies - a high whistle and a low whistle- easy to detect- tested it on fakes already many times- well duhhh
The fakes you won’t catch without cutting the bar/coin have tungsten cores. The weight is the same. Usually the technique is reserved for 100 ounce bars but some 10 and even 1 ounce bars have been found. I remember a few years ago that some bars in one of the large depositories were found to have tungsten inside. Then the information stopped with questions as to whether there were any real gold thru&thru bars left in our depositories, like Fort Knox even.
I've always wondered if there was a nondestructive way to test them, like Young's modulus:
Tungsten: 411 GPa
Gold: 79 GPa
Electrical resistivity? Gold is about three times more conductive.
Any electrical resistance test would merely go around the core tungsten finding the least resistant pathway which would be through the gold. If the Tungsten is inside the Gold cladding, it won't make any difference if the gold cladding is thick enough.
Echo testing might have a solution because the slight density difference. Also the way they get the weight to be the same is to make the bars just slightly larger to account for the different weight of the tungsten, so very carefully measuring the volume of the bar or coin and comparing the expected Gold mass to what is actually measured should give away the fake if the tungsten is buried inside.
The fakes are covered with a fairly thick gold. Some are thick enough to mask the inductance of the core of tungsten. It's particularly a problem with gold bars. 50% tungsten core is enough to make it profitable. . . which costs about $105 to add to real gold casing around it. Sell it as 100% gold Good Delivery Bar (438.9 ounces) for ~$556,000 replacing half of it with Ferro-Tungsten or Tungsten Carbide (~$150). Bank the difference. . . taking whatever risk you think you can get away with about detection using the amount of gold cladding you think is enough.
You have to be certain that where you are testing for Young's modulus is where the gold is not being faked. . . the fakery could be occurring two inches away from where you are testing the modulus. . . and you missed it. Same with drilling cores to test for purity. You have only tested the purity where you drilled. You can minimize that possibility by finding the center of gravity and assuring yourself the bar is homogenous and drilling in multiple spots. If you find that the bar balances 2/3rds or 5/8s, basically anything not centered, then you've definitely got a problem. The only absolutely certain way to test for homogeneity and purity is to melt the bar, then assay the entire melt. . . otherwise, there is still could be a question.
With this finding of trusted mint or foundry assay stamped gold coins/bars not being reliable it raises all kinds of trust problems.
Conductivity? See my comment above on that.
My DIY pinpointer is sensitive enough to tell per cent of tungsten & gold because it also measures the electric field surrounding the coin against the earth`s field, besides the inductance.
> The electrons almost all travel on the surface of a conductor, not through the core. <
You’re right, Arlis, etc. A conductivity test would be of little use differentiating between gold and tungsten. And that’s something I should have known.
Years ago I read about a sound echo test that could be used to tell the difference between gold and tungsten. I confused that test with a conductivity test. I blame Global Warming for my mis-remembering.
Anyway, that echo test is used on bars. I doubt if it would work on a small, one ounce wafer. A diagram of the sound echo test is here:
http://www.zerohedge.com/news/2013-08-16/gold-or-tungsten-heres-how-know
LOL. I normally just blame my ever increasing senility.
Not necessary. Tungsten's density is nearly the same, true. But the speed of sound in tungsten differs considerably from that in gold.
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