Posted on 12/07/2013 9:10:46 AM PST by Kaslin
Yes.
Maybe it’s just me, but when it’s advertised for sale on radio and TV, I figure there’s no real value left in it anyway.
“But gold plated tungsten would have the conductivity of gold as long as it has sufficient thickness”
Interesting point, but with a sensitive enough gauge and enough current it should be possible to tell the difference - but that gauge might be very, very expensive and finnicky.
“resistors in parallel. The equation is R total = R1 (times) R2, (divided by) R1 plus R2”
Yes, that is true, but if you have a fair thickness of gold, it becomes a much less simple matter to determine that the deviance of increasingly small variances is due to the bimetallic nature rather than some other test artifact.
As example, consider a plate of gold a sixteenth of an inch thick, and an inch by an inch! With a similar gold section a quarter inch high folded up on each end as the contacts. This will have very low resistance. Now weld a plate of tungsten on top. While that adds to conductivity per the cited equation, at that point things like shape (minute transmission distance differences) and contact become important.
You’d be better off detecting other properties, like using sound or some other vibration-based tech like a penetrating EM field to detect the interfaces between conductivities, densities, or internal reflectivity.
I suppose if you had lab-grade equipment with really high amperages, and a standard for shapes, and contact points it might work...until someone put a little silver on the tungsten.
BFL
Those conditions will only last for a short time. Gold and silver will return to currency status.
I don’t know why that exclamation point was inserted. It’s not that exciting.
I was actually referring to a college setting where lab scales commonly are accurate to .0001 grams. Volumetric devices used are scaled depending on the sample, so there is a wide range of options available. Typically, analysis is done under stand temperature and pressure, so your contention that there is disagreement regarding densities is void. But where did I even mention density testing as an analytical method? It certainly is a method that could be used, and although time consuming, would certainly provide a useful result. But if I wanted a quick and dirty test, I’d just heat it up - gold melts a couple of thousand degrees below tungsten.
Correct.
The differences are so small, they are likely to be exceeded by inherent measurement errors.
A freshman chem student ain’t gonna be able to say squat about it...
In your post #6.
Typically, analysis is done under standard temperature and pressure
Very true. After posting I also thought about the purity angle. Suppose that the "gold" bar in question was marked 99% pure. But suppose it was really closer to 98.5% pure. But the assayer's device couldn't pick the tenths place (or whatever). That would introduce an error even under STP.
So if you coated the tungsten in copper or silver to lighten it before encapsulating it in gold, you could defeat the density test, yes?
the answer to fiat currencies is gold due to the inability to quickly produce more. the issue presented here is how can the buyer be certain. tough call
another solution to fiat currencies that also provides assurances of authenticity with little effort is... crypto currencies
one such example today is bitcoin
The definitive test between Gold and Tungsten is the bend test. Gold is much more ductile.
Just so we’re clear...I agree you are correct in an ideal sense.
Oops - you are correct. It’s early...
Differences small? The difference when comparing two cubic centimeters is .03 grams - that value is 300 times what a typical analytical scale can accurately measure. It is huge.
Meanwhile, gold has less half the electrical resistance of tungsten ( 22.14 vs 52.8), and about twice the thermal conductivity ( 318 vs 173 ), so you should be able to tell the difference by comparing the suspect coin against a known-good coin.
Pre 65 US silver dimes, quarters and halves will, I think, be easier to trade with than suspect gold bars.
No worries. I probably make more mistakes before noon than most people make all day. Now, if I can only remember where I parked my car last night.
1. Tungsten can’t be formed into intricate sculptural shapes like gold. It’s extremely brittle and not ductile.
2. There has NEVER been a tungsten coin that is a credible fake of gold, with the easily measured proper weight and dimensions. (Perhaps some big bars with tungsten cores, but that’s not a consumer issue). Unimaginable to look authentic when compared side by side with the real thing.
4. If one existed, it would be an extremely valuable collector’s item, and would “ring” very differently when dropped on a surface than a gold coin it purported to be (and could not possible look like).
3. This is anti-PM propaganda.
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