/biz/ - Business & Finance

>>29189588
In addition to the things others have mentioned, you have the ping test. Balance a coin on your index finger and carefully strike it with another to hear the pinging sound it makes. Or flip the coin in the air with your thumb to hear the same. You'll get used to what a coin sounds like. 90% silver dollars have a certain chord or multiple sound frequencies it rings at, while pure silver is much cleaner.

If you wanna get *super* analytical with it, you can do the ping test with the android app spectroid. As you can see in pic related, Silver Dollars (morgan, peace) have high activity at frequencies ~4300, ~10300 and ~17500. This makes up that "chord" i was talking about earlier.