I know this has probably been posted somewhere but I don't see it. how can you tell the difference between solid silver and copper that's been silver plated?
Assuming you don't wish to saw into it ( which is what many silver buyers who are going to melt it anyway do), it is difficult if the silver layer is fairly thick. Specif gravity measurements can help since 100% copper has a specific gravity of 8.96 and pure silver has a specific gravity of 10.49, any mixture wiull be between these 2 marks. sterling silver ( 92.5%) has a specific gravity of 10.36, and 90% silver ( most US silver coins) has a sp.gr. of 10.31. On the other end, if there was 10% silver plating ( rather high amount) on 100% copper, a rough sp. gr. would be about 9.09. If it was not a plating, but a homogenous mix of silver and copper, you could use acid solutions. Specific gravity testing doesn't harm the coin or bar. Jim
In order to have certainty that your coin is legit without damaging it you'll need to do a lot of tests. Diameter, thickness (height), weight, specific gravity, and then either the ice melt test (silver as the best conductor of heat will cause melt ice to faster at room temp than a non-silver coin) and/or the rare earth magnet test (at a slight incline the magnet will slide with a slight resistance on a silver coin vs. on a fake it will still slide of quickly).
Maybe the sound of the coin when you (kindly ) let it drop on some piece of glass is not exactly the same. IMHO, silver noise is quite typical ( and pleasing ! ) Just try and tell Cheers Philippe
If the coin has a reeded edge, you can see the copper by looking at the edge. Otherwise, I would go with the weight method. Also, a book will tell you the make-up of most denominations by the year.
