Crown gold
Encyclopedia
Crown gold is a 22 karat
Carat (purity)
The karat or carat is a unit of purity for gold alloys.- Measure :Karat purity is measured as 24 times the purity by mass:where...

 (kt) gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...

 alloy
Alloy
An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...

, introduced in England for gold crown coin manufacture in 1526 (by Henry VIII
Henry VIII of England
Henry VIII was King of England from 21 April 1509 until his death. He was Lord, and later King, of Ireland, as well as continuing the nominal claim by the English monarchs to the Kingdom of France...

). It is 22/24 = 0.91667 fine or 91.667% gold.

Previously, gold sovereign coins were made from 23 kt gold, but this was soft and invited deliberate filing, and also non-intentional wear. The 22 kt standard has been used for British gold coin
Gold coin
A gold coin is a coin made mostly or entirely of gold. Gold has been used for coins practically since the invention of coinage, originally because of gold's intrinsic value...

s ever since this change.

Alloying metals in England and the United Kingdom

The alloying metal in England was and is traditionally copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

-only, although a component of 1.25% silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...

 replacing the same weight of copper, as a softening agent, was briefly used in gold sovereigns in the single year of 1887, for better production of an image of Queen Victoria for the Golden Jubilee
Golden Jubilee
A Golden Jubilee is a celebration held to mark a 50th anniversary.- In Thailand :King Bhumibol Adulyadej, the world's longest-reigning monarch, celebrated his Golden Jubilee on 9 June 1996.- In the Commonwealth Realms :...

 of her reign. Crown gold with copper as the only alloying metal other than gold, remains the standard used in the British gold sovereign, which is still minted.

Alloying metals in the United States

In the United states, gold circulating coins were minted in 22 kt. gold alloy of crown gold purity, until 1834. These pre-1834 U.S. coins differed from their English counterparts in containing a significant component (about 6%) of silver.

In 1834, the fineness of U.S. coin gold was decreased from 22 kt to 0.8992 fine (21.58 kt) to discourage coin melting. In 1837, all silver was removed from U.S. gold coins and the gold content increased slightly to 0.900 fine (21.60 kt exactly). This 90% gold-copper alloy continued in the U.S. from 1837 until gold coins were removed from circulation in the U.S. in 1933.

Pure gold bullion coins departing from crown gold or alloy gold standards

Before the mid twentieth century, all gold coin
Gold coin
A gold coin is a coin made mostly or entirely of gold. Gold has been used for coins practically since the invention of coinage, originally because of gold's intrinsic value...

s were intended to circulate as money and therefore contained either 90% gold or a 22 kt crown gold type alloy. Bullion coin
Bullion coin
A bullion coin is a coin struck from precious metal and kept as a store of value or an investment, rather than used in day-to-day commerce. Investment coins are generally coins that have been minted after 1800, have a purity of not less than 900 thousandths and are or have been a legal tender in...

s were subsequently designed as collectable and not for circulation, which could be much more pure, since wear-problems were not an issue. Some of these gold bullion coins are pure gold of 24 kt, 0.999, 0.9999, or even 0.99999 fine (see Canadian Maple Leaf
Canadian Maple Leaf
The Canadian Maple Leaf coins are bullion coins of gold, silver, platinum, or palladium. The coins are issued by the Royal Canadian Mint.-List of coins:*Canadian Gold Maple Leaf*Canadian Platinum Maple Leaf*Canadian Silver Maple Leaf...

).

Return to crown gold for some bullion coins

The South African Krugerrand
Krugerrand
The Krugerrand is a South African gold coin, first minted in 1967 to help market South African gold. The coin, produced by the South African Mint, proved popular and by 1980 the Krugerrand accounted for 90% of the gold coin market. The name itself is a compound of Kruger and rand, the South...

, first produced in 1967, and the first of these modern coins, was produced in the exact traditional crown gold recipe of 22 kt gold (remainder copper), because it was originally intended to circulate as coin currency. The Krugerrand is now considered primarily a bullion coin, and as such has no face value imprinted on it. A few other gold bullion coins never intended for circulation have also been produced for purely historical reasons in the traditional crown gold purity, including the gold sovereign (in exact gold/copper historical ratio), as well as now the American Gold Eagle
American Gold Eagle
The American Gold Eagle is an official gold bullion coin of the United States. Authorized under the Gold Bullion Coin Act of 1985, it was first released by the United States Mint in 1986.- Details :...

series of bullion coins, the latter which again now follows the original (pre-1834) 22 kt or 0.91667 fine gold standard (although its silver content of 3% is somewhat different from that of any coin the U.S. had ever previously produced).
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