Gold Investment - Gold Purity and
Weight
Gold bullion
coins never consist 100% of pure gold. The reason for this,
is because gold alone is too soft to use in jewellery or to hold a form. It is therefore necessary to alloy gold
with other metals such as copper, silver, nickel, zinc, etc. to make it harder and more durable. This
combination of gold with other metals is called "gold alloying" and the final compound is called "gold alloy" if
it contains more than 50% gold.
The Purity of Gold
The modern way of denoting the purity of gold, platinum and silver
alloys are through a system called Millesimal fineness.
This system denotes fineness which is a measure of the weight of pure gold per 1000 parts. The
millesimal fineness system has not replaced the older carat system yet, but steps are being taken in that
direction. The main reason for this, is because the millesimal fineness system is more accurate in
denoting the purity of gold alloy.
For example, a gold alloy that's denoted as "750," using
one of the percentage hallmark stamps used in many European countries, contains 75% gold. This is equal
to the "18K" used in the United States, which is an extension of the older carat system of denoting the purity
of gold by fractions of 24. "18K" is therefore in reference to 18 carat or karat in North American spelling.
"18K" or "18 carat" means that there are 18 parts pure gold and 6 parts other metal in the relevant gold
alloy.
The purest form of gold, according to
the millesimal fineness system, is denoted as "999.99" and as "24K" or "24 carat" according to
the older carat system.
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