Like our brethren the stamp collectors, numismatists especially treasure specimens that result from manufacturing errors. Given the high quality standards involved in coin production, the novelty and rarity of a misprinted coin cause it to have far greater value than one that is correctly formed. This enthusiasm was recently injected into state quarter collecting with the discovery that some Wisconsin state quarters seem to bear an extra "leaf" on the ear of corn, the result of fortuitously-placed chips in the die. Read more and see pictures in the following news articles: