Collectible coins from the United States include a variety of denominations, with the 25-cent piece (quarter dollar) being particularly popular among collectors. Mint sets, specifically from the year 2012, comprise uncirculated coins produced by the U.S. Mint, showcasing the year’s designs and intended for collectors. These sets often include coins from different mints, such as Philadelphia and Denver, and may also feature special commemorative designs that reflect historical events or national symbols. Collectors value these sets for their quality and potential appreciation in the numismatic market.