Guinea coin

A guinea is a former British British gold coin. First struck in 1663 its value was set by the market price of gold, it was one of the first machine milled coins in Britain. 44 and one half guineas would be made from one Troy pound of 11/12 fineness gold, each weighing 129.4 grains. It was revalued to 21 shillings, or £1.05 in 1717. It was named after the purported source of much of the gold of the initial minting (now Ghana). The last of such coins were minted in 1813.

Even after the end of its use, the name was long used to indicate the amount of 21 shillings. The guinea had an aristocratic overtone; professional fees and payment for land, horses and art were often quoted in guineas until decimalization in 1971. It is still quoted in the pricing and sale of race horses.

The two guinea piece was introduced in 1664 (to 1753), with the five guinea in 1668 (to 1753), the half guinea in 1669 (to 1813) and the quarter guinea (1718, 1762).