What this coin looks like (obverse, reverse, mint mark location, special features, etc.): There was a major Doubled Die Obverse (DDO) error on some 1937 Washington Quarters. This is best identified by the strong doubling of the words "IN GOD WE TRUST". The 1937 date is also slightly doubled as well. An example image of this coin is depicted above. Source of example image is courtesy of Heritage Auction Galleries.
Coin valuation chart: Typical coin prices, values and worth per grade or condition - in USD