What This Coin Looks Like (Obverse, Reverse, Mint Mark Location, Special Features, etc.): There were a few major varieties of the 1820 Capped Bust Dime. The two major ones deal with the size of the zero "0" on the 1820 date. One variety had a larger "0" which lines up with the bottom of the "2" and appears larger and wider. The small "0" is smaller and doesn't line up with the "2". The difference between the 1820 small 0 vs large 0 capped bust dime is depicted in the example image above.
Another variety was the 1820 "STATESOFAMERICA" dime which has no spacing between the words "STATES OF AMERICA" on the reverse of the coin.