Geocoins are specially minted coins designed by geocachers and traded and collected. In some regions, geocoins of any type are very rare. Most are collectable.
Among the most sought after are Moun10bike geocoins, which are the first ones.
Most geocoins are trackable on various websites. The only trackable geocoins on the Geocaching.com web site are the USAgeocoins and Moun10bike geocoins.