# Lifestyles & Discussion > Open Discussion >  Pingcoin: Must-have app for gold/silver testing

## ClaytonB

I just discovered pingcoin. This app is incredible! And it's free! Great library of coins. Just install the app on your phone, select your coin from the list, grip the coin between your index and thumb and then gently ping the rim at an angle with a wood pencil or something equivalent (no damage to the coin itself). Together with calipers to measure the dimensions of your coin, you can test any coin in the library with complete confidence -- if there's a fake in your stack, it _will_ be detected...

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