1859 Thin Planchet

The 59's were struck on thinner planchets than other large cents. There were lots of complaints on the weight of the coin so the mint upped the weight from 1876 forward to match the British 1/2d. Now if you are talking 50 or 60% thinner than other 59's that's something else. You can thin a coin, post mint, by placing it in an acid. The coin etches equally so there is not a loss of detail, just a general thinning.