Since January 2004, "collectors' euro coins" has been used to refer to coins that are not intended for circulation, usually minted in precious metals, with a nominal value and design that are different from those intended for circulation.
They must also differ appreciably from those in circulation in at least two of the following three characteristics: colour, weight and diameter.
Commemorative coins on the other hand are coins intended for circulation as legal tender throughout the euro zone, which meet the following conditions:
The first commemorative euro coin issued in Spain was to mark the quatercentenary of the first publication of the work The Ingenious Hidalgo Don Quixote of La Mancha.