Hello ; I think that the first thing you want to know about a coin is the metal in which the coin is made ...Knowing the specific gravity of a metal aid us to identify excatly what is ;but most coins are made from alloy(mixture of 2 ou 3 metals) so the specific gravity don't do well in most cases. Are there any methods without using tools to identify the metal of a coin( color ,brightness,effect of water on the metal ,any changement in color with time , the effect of air ..ect).
Learning the spefic gravity weight of coins is only done by a very limited number of people, and usually this type of test is only used when authenticity of a coin is in question. Most people work backwards from coin itself. There are many referrence books which will give the dimensions and weights of the coins. So once you identify what kind of coin you have, you can determine the correct information for it. For American coins it is easy to spot the difference between silver coins and the modern (1965-date) clad coins because of the copper core seen on the edge of the coin. Now I never recommend this, but silver also has a different ring than clad coins. You can flip the coin, or drop it on a table and you can hear the difference. Now the short answer is knowing what type of coin you have. Once that is determined, using tools such as a scale and caliper to identify if authentic become easy. Hope that helps.
Flip a Morgan dollar and you will hear a nice sounding "ping"...it is what I use for coin flips (especially football games). Silver sounds much better than clad coins. Matter of fact...you should see the kid's look when I use a Morgan dollar for the game time coin fllip. Kids that should be concentrating on the game will ask, "What is that?" or "How old is that?". ...a new collector is born, now let the game begin.
