[GBA]

Good post. I was wondering about the same things. For example, a 90% silver quarter sounds very different compared to newer clad quarters and the same is probably true of .999 fine Eagle and a tungsten core counterfeit. I have no idea what a bar would sound like, but if I could afford one, I'm sure I could afford some way to make sure it is what the stamp on it says.

From Goldprice.org:

You can test the purity of gold yourself with the right test equipment. Mostly this consists of acids which you can purchase for that purpose although electronic testing is now becoming popular and electronic testers can be found with a little investigation and research and purchased. The cost of the test equipment means that you would want to test a lot of gold to warrant the cost of the equipment and along with the other factors such as safety measures, time involved etc, you would likely be better off just getting an independent jeweler or laboratory or even a Mint to test the gold for you.

[Toddsterpatriot]

You can test the purity of gold yourself with the right test equipment. Mostly this consists of acids which you can purchase for that purpose

Are you going to dissolve the entire bar?