Geocoins are trackables that come in the form of a coin. Usually made from metal, some wooden varieties do exist.
The first geocoin ever circulated on Geocaching.com was the Moun10Bike Geocoin #002, released on September 20th, 2001 by Moun10Bike. Until 2005, trackable geocoins were made primarily by organizations or companies. In 2005, Geocaching.com made tracking codes available to buy by users, widely increasing the use and popularity of geocoins. Minor changes over the years from Geocaching.com have mainly focused on altering the minimum number of coins needed to purchase trackable codes and unique icons. Currently, 50 is the minimum requirement.
Geocoins can go missing for a variety of reasons: theft, forgotten, lost, muggling. The best way for a geocacher to help prevent a geocoin from going missing is to learn how to handle them when found. Check out the Guide to Geocoins to learn what you can do to help prevent this from occurring.
Most coins usually have a picture or other unique visual features. They may represent a variety of things from raising awareness for certain diseases to helping out after a natural disaster to personal artwork. Over the years, geocoins have also increasingly seen non-traditional coins, or trackable geocoins that do not confirm to the traditional circular coin shape.
For an additional fee, geocoin designers can also have a unique icon attached to the coins on the Geocaching.com website. Many geocachers will discover geocoins to collect these icons on their profile.
Although geocoins are relatively cheap to produce, the artwork and rarity of certain geocoins may making them a target of theft. Some geocachers also collect geocoins, carrying them with them to events for other geocachers to discover.
Several ways that geocachers have combatted the theft of geocoins include to physically damage the released coin by drilling a hole to attach something, or releasing proxies. Physical alteration reduces the value of the coins, presumably making them less valuable to steal.
The original Moun10bike coin is officially owned by user Moun10bike. All of the coins are activated under his account and he has been known to lock down a coin's page when he finds that a particular tracking number has been sold without permission. Some of them have been rumored to sell at values in the thousands of USD.
There is an increasing number of geocoins available. Check out the Guide to Geocoins to see a current list of circulating geocoins.