The Guinea is a famous British gold coin minted between 1663 and 1814. The coin was originally created as a one pound coin (20 shillings) but is better known as being worth One Pound and One Shilling (21 shillings).
After the English Civil War, King Charles II introduced new coinage. A gold coin, approximately a quarter of an ounce, was issued and for the first time it was not hammered. Made by machine using gold from the Guinea Coast of West Africa the coin probably became the most important coin of the realm.
Originally 20 shillings, the coin actually fluctuated with the gold price, at times being as high as 30 shillings. In 1717 the Guinea became fixed at 21 shillings (in today’s money that is £1.05). Other coins of the family were also minted, such as half-guinea, two-guinea and five-guinea.
In the Great Recoinage of 1816 the Guinea was replaced by the Pound and the Sovereign became the gold coin in use. Long after the Guinea was retired the name continued to be used, especially for prestige purchases intended for the more wealthy. Even now racehorses are still sold in Guineas (the auctioneer traditionally taking the 5p as commission).
Guineas are 25mm in diameter, weigh about 8.38g and are 22 carat gold (91.6%). Prior to 1717 they weighed slightly less (around 8.3g) and were made of 91.34% gold.
On eBay UK:
 | 22ct Yellow Gold 916 Full Sovereign 1968 £ 840.00 |
 | Bullion Gold Half Sovereign Best Value £ 430.05 |
 | 2000 Gold Full Sovereign Millennium Return Choice BU Low Mintage Royal Mint £ 830.00 |
 | 2021 ELIZABETH II GOLD SOVEREIGN - STRUCK ON THE DAY LOW MINTAGE £ 899.20 |
 | 1870 Queen Victoria Gold Sovereign Coin - Shield Reverse, Uncertified £ 975.70 |
 | 1925 Gold Sovereign Coin King George V 22ct 7.98g £ 812.00 |
 | 1982 Elizabeth II Gold half Sovereign Coin, Era 1952-2022, Uncertified £ 491.20 |
 | Gold Full Sovereign 2021 BU NGC MS69 Coin Britain UK Royal Mint Uncirculated £ 1,048.00 |
On eBay USA:
| 22ct Yellow Gold 916 Full Sovereign 1968 £ 840.00 |
| Bullion Gold Half Sovereign Best Value £ 430.05 |
| 2000 Gold Full Sovereign Millennium Return Choice BU Low Mintage Royal Mint £ 830.00 |
| 2021 ELIZABETH II GOLD SOVEREIGN - STRUCK ON THE DAY LOW MINTAGE £ 899.20 |
| 1870 Queen Victoria Gold Sovereign Coin - Shield Reverse, Uncertified £ 975.70 |
| 1925 Gold Sovereign Coin King George V 22ct 7.98g £ 812.00 |
| 1982 Elizabeth II Gold half Sovereign Coin, Era 1952-2022, Uncertified £ 491.20 |
| Gold Full Sovereign 2021 BU NGC MS69 Coin Britain UK Royal Mint Uncirculated £ 1,048.00 |