This appears to be copper and is the size of a quarter with a smooth edge. Someone told me that back in the day newspaper salesman would use these in the paper machines if they had to open them to give someone a paper that lost their money or work on it for some reason. Story sounded plausible... but not sure.
Edge: Smooth
Weight: 6 grams
Diameter: 24.3 mm
Thickness: 1.6 mm
No raised rim

