The 1827 Quarter Dollar restrike is one of the classic rarities of American coinage. Technically, this is not a restrike in the purest sense of the word; rather, it is a muling of an obverse of 1827 with an old reverse from 1819. Thus, the restrikes are easily recognized by the square base 2 in 25C on the reverse (originals have a curl base 2). Die evidence indicates that 1827 Quarters were restruck on at least two different occasions. Period One restrikes are from a relatively clean, unrusted state of the dies. At least two of the Period One restrikes were struck over 1806 Quarters. Karl Moulton believes these were made specifically to test the efficacy of the close collars that were soon to come into use on all U.S. coins. Period Two restrikes are from heavily rusted dies.