Guinea (coin) The guinea was a coin of approximately one quarter ounce of gold that was minted in Great Britain between 1663 and 1814. The name came from the Guinea region in West Africa, where much of the gold used to make the coins originated. It was the first English machine-struck gold coin, originally worth one pound sterling, equal to twenty shillings, but rises in the price of gold relative to silver caused the value of the guinea to increase, at times to as high as thirty shillings. From 1717 to 1816,