Hi folks, I recently bought a bunch of coins from Maylasia and surprise, surprise, some of them are fake. It's really easy to pick up on the fakes that don't even weigh what they're supposed to weigh, but I'm having trouble making a clear call on the others. None of the coins are magnetic and quite a few are very close to their Krause weights, either a little more or a little less, and the size of the coins is accuarate. Is there a metal out there that counterfeiters use that's close in weight and size to silver? It's possible I have a few genuine coins here, but I'm trying not to be too optimistic.... lol.
Yes there are a few metals that are close to silver in weight. Just look at the periodic table to see them. And you can make alloys all day long of the same weight. Most mints had tolerances of around 1%, so when you say they are close, are they that close ?
Sorry, Doug, but densities are not on the periodic table and it has nothing to do with the atomic weights. Aside from that, you are quite correct about the alloys.
Yes, it's true... the ultimate goal is to make the coin the right weight. But think of it like this : Since a counterfeiter will have no problem making a coin of the right dimensions, the fake will also match a real one in volume. That being so, the way to be close in weight is to use an alloy close in density to the silver alloy used for authentic coins. A periodic table will be of no help unless it shows the element's density. I personally have never seen that, but perhaps they do exist (only for the solids and liquids, of course). Neither the atomic number nor the atomic mass are of any interest. When you say "close to silver in weight", what you really mean is close to silver in density. That information is typically not on a periodic table and cannot be inferred from the info that is there. There are several sources for density of metals. I have a Perry's Chemical Engineer's Handbook around here somewhere... I bet they might have something.
The periodic table list the atomic weight of the metals. Silver is 107.86, tin is 118.71, copper is 63.54. This tells you that you can mix a little copper with a little tin and have ametal that weighs the same as silver. Yes you can figure the same thing out with density or the weights of metals. But the periodic table does provide the info you need.
Sorry, Doug. Atomic weights are not related to the density. If that were the case, Uranium would be the densest element instead of osmium. Silver = 10.5 Tin = 5.75 or 7.28 Copper = 8.92 You can mix them anyway you want to and they will never be as dense as silver. If nothing else, just look at tin. It has 2 different densities depending on whether it is white tin or brittle tin.
Most of these were large "silver" coins with an average weight of about 28 grams. One was 0.7 of a gram less then the book numbers, and quite a few were plus or minus .03 of a gram. Minus I could see, but plus? Dirt maybe? lol
That is true. However, any resulting alloy would be more expensive than using real silver. The volume situation mentioned above is important along with the weight, and that is why most goldsmiths, jewelers, etc. use specific gravity values for comparison to real, as it incorporates both weight and volume. So worn coins (grade poor) could be determined as to their silver or gold content without concerns of diameter,etc. as their volume would be measured. A "gold" chain could have a plate of 18K and test "gold" with acids or meter, but a specific gravity test would determine if it was 18K throughout, or much less inside. Jim
The presence or absence of the density on the Periodic Table depends on which Periodic Table you use. The Large ones I used when I taught chemistry had a wealth of information on them. Obviously, a small one in a book can't have all the data that a large one has.
Most of the coins in question are supposed to be between 0.5 and 0.7 silver content. I guess that only helps to confuse the issue of authentification. Either way, if some of the proper weight coins are fake, someone went to an awful lot of trouble to fake coins that aren't worth much more then their bullion value. Interesting responses, guys... I'll post a few later this evening when I get home from work along with their size and weights.
Tolerance levels allow the discrepancy in either direction. For a 28gm coin tolerance should be pretty close to 0.28gm. So if yours are over/under .03 then they are right there at the edge.
In reality your the closest to what is sometimes done. Many, many metals and sometimes not even metals are used to counterfeit coins. What everyone here is missing is the fact that most counterfeiters really don't care about the weight of the coins. For example I've purchased fakes that were pure Lead of a Standing Liberty Half. It was so funny and bad of a fake that I couldn't resist buying the stupid thing. What some do is to mix just about anything to make a coin and then, if necessary, plate the thing. In China there was a counterfeiter making Silver Dollars out of pure Silver. The intent was to sell as a rare date, not the fact that it was a erroneous metal. May have used $10 or more in metal but sold the coins for hundreds and the buyers thought they were cheating someone by buying a thousand dollar coin for a few hundred. Not always metals are used also. For example Bronze is a combination of metals and occationally Silicon, Phosphorus, etc. are also a part of the mixture. The main problem here is your all mixing up criminals with chemist or a physics major. Crooks just don't care about the contents of coins. Only if they can sell the stupid things to stupid people. And they do.
I've seen a few fake Morgans that were correct in weight, and it's not because of a good chemist somewhere in China. It's because they were made with silver. Silver is cheap. You can buy culls all day long for peanuts, turn around and restrike them into fake rarities and sell them (or try) at a very sizeable profit. I would think this route would be cheaper than formulating an alloy that would never pass all the tests that a genuine coin would regardless of how well it's made. Guy~
how do I recognize a fake if I don't have the details on that specific coin? is there any website i can check it out
