You've found a piece of pottery at the antique mall and it looks pretty good, but you're not sure if it has a hairline crack or just a little crazing.
How about giving it the sound test? Flick the jar with your index finger and see what kind of sound it makes.
Does it ring like a bell or is it a flat sound? A crack in a jar (even tiny ones) will make a very flat sound. Whereas a "good" jar will ring clear.
As a demonstration, in this sound test, I am using two jars recently purchased via eBay. Both were advertised as excellent condition. When I received them one was definitely in excellent condition and the other had a very tiny line on the rim only. When I did this test, I held the jar in my left hand and flicked it with my index finger and thumb on my right hand. Both jars were about the same distance from the microphone and both were "flicked" the exact same way.
Listen to the difference in the Plink or Plunk test!
