The first gold two pound (£2) coins appeared in 1820 for George III but they were only made occasionally (intended for circulation) until 1980 when the Royal Mint started minting them yearly. There are both proof and uncirculated types in previous years but the modern trend seems to be a proof as part of a set.
Gold £2 Coins are also know as Double Sovereigns, but as with gold five pound coins there are two variations. One is the double sovereign itself - it looks like a larger version of the sovereign of the same year and is likely to have George and the Dragon on the back. The other type is a commemorative style which tends to copy the circulation two pound design. To avoid categorisation some dealers refer to both types collectively as two pound pieces.
For size comparison, the image on the right shows a modern sovereign set containing the half-sovereign, sovereign, double sovereign and £5 coin.
The specification for two pound coins
Weight is 15.98g, which is twice the weight of a standard gold sovereign. The diameter is 28.4mm and about 2mm thick. It is made from 22 Carat gold (0.916 or 91.6% gold).