The Guinea was a British gold coin minted by the Royal Mint between 1663 and 1814. ???Guineas??? were so-called because the gold used in making some of them came from Guinea, West Africa and they were minted in four denominations (a half, one, two and five).When first introduced the value of the guinea was 1?? (20 shillings), however the value of the coin fluctuated with the value of gold.