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For the second time now I've heard of older cash registers having a marble slab as a means of slug detection. Knocking a silver coin on the marble made a much different sound than other metals (guess it's similar to a ring test).

Anyone try this method for counterfeit detection? I might pick up a marble tile and try this out, though it appears the test may require a piece of copper, wood, and/or open space below.

jmaii wrote:For the second time now I've heard of older cash registers having a marble slab as a means of slug detection. Knocking a silver coin on the marble made a much different sound than other metals (guess it's similar to a ring test).

Anyone try this method for counterfeit detection? I might pick up a marble tile and try this out, though it appears the test may require a piece of copper, wood, and/or open space below.

makes good sense. The ring test is a good, quick, inexpensive and dependable test for weeding out "suspect" coins, but would prove worthless for detecting alloys with a similar sound signature... if they have been developed.