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 Replies: 10 / Views: 2,286 |
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Pillar of the Community
Philippines
1156 Posts |
How does one test gold coins if genuine? is there another way aside from by weight? thanks
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Pillar of the Community
United States
511 Posts |
You can use acid to determine real gold from the fake stuff.
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Bedrock of the Community
United States
10982 Posts |
The high density of gold makes it very difficult to replicate. Density is mass/volume and the density of pure gold is 19.3 g/cm^3 at normal temperatures.
All raw gold coins should be verified against known specifications for weight and dimensions. Normally this would be the diameter, thickness and weight in grams. If these measurements are in tolerance (+/-1%), then there's a 99.9% likelihood you have gold.
This does not mean the coin is genuine of course. It only means it is gold.
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Moderator
 Australia
16809 Posts |
There are various kinds of "acid tests" you can do to gold objects, both electronic and visual, all of which are variations on the ancient "touchstone" technique: they all rely on scraping a small amount of material off the surface of the object. This damages the object in question, so for a coin collector they are to be avoided if at all possible, just like we wouldn't recommend the "Old Prospector method" of biting it with your teeth (gold is a soft metal and would "bite" much easier than a non-gold fake). Acid tests also won't detect the difference between a solid gold object and something that's merely gold-plated.
Weight and size alone is a reasonable way of discerning a gold coin because, as bherring says, gold is much denser than just about anything else you could make a fake coin from. A fake gold coin made of something other than gold would have to be either suspiciously lightweight, suspiciously large, or suspiciously thick. There have been rumours of fake plated-tungsten gold bars doing the rounds (tungsten is one of the few metals which have the same density as gold), but tungsten is still seen as being too expensive and difficult to work into an object as small as a coin.
You could get yourself a specific gravity rig to estimate the fineness of the gold, but since you need an accurate balance as part of that rig, you may as well just use the balance for simple weighing.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
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Pillar of the Community
United States
2661 Posts |
Still be careful. I have seen coins made of real gold, good weight and dimensions, but were still fakes. I was shown one such fake yesterday. A gold eagle made by someone called "The Omega Man". Left his signature on the inside of the "R" in liberty he did.
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New Member
United States
15 Posts |
I read the Omega Mans forgeries are of such high quality some people collect them
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Bedrock of the Community
United States
20753 Posts |
Quote:
There are various kinds of "acid tests" you can do to gold objects, both electronic and visual, all of which are variations on the ancient "touchstone" technique: they all rely on scraping a small amount of material off the surface of the object. This damages the object in question, so for a coin collector they are to be avoided if at all possible, just like we wouldn't recommend the "Old Prospector method" of biting it with your teeth (gold is a soft metal and would "bite" much easier than a non-gold fake). Acid tests also won't detect the difference between a solid gold object and something that's merely gold-plated.
Unfortunately very true that MOST tests require damage to the object. I've always wondered about that biting a Gold Coin with your teeth thing. Back in the old days most people didn't have great teeth and I could easily see broken teeth if that was attempted. I've already had aabout 5 crowns from popcorn so I imagine if I tried the biting of Gold coins, I'd have a mouth full of fake teeth to match any fake coins. So far I havn't heard of to many counterfeited Gold Coins made with real Gold or at least not yet. It has become common for some in China to use Pure Silver to make our Dollar coins since they are planning on selling them for collector purposes and that profit is enormous. This may also be true of Gold Coins even now and if made well, not many would be able to tell. One of the really good reasons to purchase slabbed coins I guess. |
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Bedrock of the Community
United States
17884 Posts |
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I've always wondered about that biting a Gold Coin with your teeth thing. Most people misunderstand the coin biting thing. They think you were biting the con to see if it was gold and if it was your teeth would make a mark and if it did then it was good. That wasn't it at all. You were biting to see if it was gold plated LEAD. Yes you CAN bite down hard enough to make a mark on a gold coin, but if you bite a gold plated lead fake you can use a much gentler bite and make a much bigger mark. SO what you actually did was bite it GENTLY and see if it made a mark. If it did you rejected it as a fake. |
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Pillar of the Community
Canada
3692 Posts |
Speaking of coin biting, how many old gold coins still have teeth marks on them? We should get some numismatists and dentists and anthropologists in one room and try to unearth some history.
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New Member
Canada
18 Posts |
Well thanks I have a medal from Chuck E Cheese that I came across so they say it is real gold but thanks to you I can now test it and check if its is brass or gold! Well, thanks a lot.
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New Member
Belarus
30 Posts |
If the goods an exclusive - that I demand the certificate from the seller. If it is not present, examination is spent at my expense that is reflected in the final price
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Replies: 10 / Views: 2,286 |
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Posted 03/20/2010 01:24 am
