guinea

The guinea (; commonly abbreviated gn., or gns. in plural) was a coin, minted in Great Britain between 1663 and 1814, that contained approximately one-quarter of an ounce of gold. The name came from the Guinea region in West Africa, from where much of the gold used to make the coins was sourced. It was the first English machine-struck gold coin, originally representing a value of 20 shillings in sterling specie, equal to one pound, 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, its value was officially fixed at twenty-one shillings. In the Great Recoinage of 1816, the guinea was demonetised and the word "guinea" became a colloquial or specialised term. Although the coin itself no longer circulated, the term guinea survived as a unit of account in some fields. Notable usages included professional fees (medical, legal, etc.), which were often invoiced in guineas, and horse racing and greyhound racing, and the sale of rams. In each case a guinea meant an amount of one pound and one shilling (21 shillings, £1.05 in decimal notation). Origin The first guinea was produced on ; a proclamation of 27 March 1663 made the coins legal currency. One troy pound of (0.9133) fine gold (22 carat or 0.9167 pure by weight) would make guineas, each thus theoretically weighing 129.438 grains (8.385 grams crown gold, 7.688 grams fine gold, or 0.247191011 ozt (troy ounces) fine gold). The coin was originally worth twenty shillings (one pound), but an increase in the price of gold during the reign of King Charles II led to the market trading it at a premium. The price of gold continued to increase, especially in times of trouble, and by the 1680s, the coin was worth 22 silver shillings. Indeed, in his diary entries for 13 June 1667, Samuel Pepys records that the price was 24 to 25 shillings.