Geocoin
A geocoin is a metal or wooden token minted in similar fashion to a medallion, token coin, military challenge coin or wooden nickel, for use in geocaching, specifically as form of a calling card. Many of these are made to be trackable on various websites to be able to show the movement around the world and visitors to be able to leave comments when they find the coin. Each coin has a unique tracking ID, which can also be used when logging it to a designated website. A geocoin typically has a diameter of to and a thickness between  and . Coins with the size of are called microcoins, because they fit into microcaches (e.g. film canister). The smallest geocoins with a diameter of are called nanocoins, and have been sold since 2009. If the diameter is larger than the geocoin is called macrocoin, and contains the saying of "that's not a coin it's an anchor". Signature items. Personal geocoins are a personal signature item that normally bears the geocacher's handle and personal design. Geocoins are often minted by caching organizations and companies. Though not specifically a personal signature item they are a form of signature item  for the organization that developed them. However, most are custom-made for geocachers, usually in batches of 100 pieces or less. Reviewer/Moderator/Lackey Coins are another form of signature items over the years these have their own following. Many of them have taken the time to create their own signature item. In the first few years the number of coins that were a signature item for a geocaching group, or individuals far outnumbered the coins that were made to sell. However now they tend to be smaller percentage as the industry has a number of coins manufacturers that develop  coins for events, holidays, or special coins. The cost to make a personal coin is fairly high. Tracking websites. When a cache listed at geocaching.com contains a geocoin, an icon (often unique to the type of the coin) is shown on the cache page's "Inventory" section. This icon will also appear in the inventory of any cacher holding one as well as in each cacher's historical trackable item listing. Icons will also remain in the inventory of cachers who log the 'discovery' of a geocoin's number without physically removing it from a cache. "Icon collecting" – the act  of having these icons listed in one's trackables listing – is an associated hobby. Many people bring geocoins with unique icons to geocaching events so that others may see the coins and use the tracking number to collect the icons online, and it is not uncommon for collectors to activate some or all of the coins in their collections in order to have a matching online collection of icons associated with their geocaching.com accounts. Other websites for trackable coins have included the 2002Canadian geocoin, Utah geocoin, Oregon State coin, and sigitem.com. Free tracking service for coins and other items is  available from Geokrety, with full service for geocaching sites such as opencaching.us, and partial service for other geocaching sites. An owner of geocoins can also set up his own website to monitor these moving mementos. Theft. It is not uncommon for activated, released geocoins to go missing, whether because a cacher is unfamiliar with the logging and tracking process or due to outright theft. Some geocoin owners will purposefully attempt to destroy the resale value of the coin by drilling and tagging it with an extra tag, marker, or other item that is intended to underscore the fact that the  geocoin is meant to travel, not to be kept. Another somewhat controversial anti-theft measure is to create a copy of the geocoin, releasing the copy and keeping the original. In 2012, a geocoin helped authorities return stolen items to a geocaching enthusiast in Seattle, who marked the coins as missing online. The goods were found in a storage unit during a raid and the geocoins became instrumental in connecting the burglars to their crime. The Ginormous Geocoin is 46 inches in diameter, made of cast iron spray-painted GOLD, and weighs about 115 pounds. The geocoin code is engraved  along its rim (the code consists of 4 letters, 1 number, followed by a final letter).