What this coin looks like (obverse, reverse, mint mark location, special features, etc.): One major variety is the 1934 D Silver Peace Dollar with a Doubled Die Obverse (DDO) error. This coin features a doubling of various features on the obverse of the coin. One way to identify this coin is to note the strong doubling of the letters "D" and "W" in the words "IN GOD WE TRUST". The Liberty head portrait is also doubled slightly as well. The easiest way to spot this is to view the two right-most spikes of the crown. There are two extra smaller underlying spikes to the left of the two primary spikes. The forehead/nose and lips of the liberty face is also doubled as well. These features are depicted by the arrows in the example closeup image above.
Coin valuation chart: Typical coin prices, values and worth per grade or condition - in USD