Dan K. asks: I have a 1942 quarter. I weighed it against one of the newer ones, and the 1942 one weighs more. Is the 1942 quarter all silver?
The 1942 quarter is .900 pure silver and .100 copper and weighs 6.25 grams. The copper-nickel quarter, minted from 1965 to the present, has an outer layer of .750 copper and .250 nickel and an inner layer of pure copper and weighs 5.67 grams.
It should be noted that when coins were intrinsic, that is they were a weight of precious metal, it was very important that the weight and fineness standards were adhered to. There existed an Assay Commission whose sole job was to randomly check coins for standard. Since modern coins are essentially tokens, the weight standard is quite sloppy and it is possible that your CuNi quarter could weigh slightly above or below 5.67 grams.
