What Is the Number 925 for Gold?

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The chemical symbol for gold comes from a Latin word meaning "shining dawn." It has become synonymous with avarice. Pure gold is for kings, but jewelers prefer to work with alloys of gold -- gold mixed with other metals.

Gold Alloy

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From a jeweler's point of view, gold has some problems. Mostly, it is too soft -- which means a jeweler's finished product may not hold its shape. Pure gold bends easily and scratches easily. The solution is to alloy gold with a little of some other metal so the alloy would be easy to work but the finished product would be hard and scratch-resistant.

Hallmarks

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In most countries, it is illegal to falsely hallmark a metal object. To convert hallmarks to percentages, put a decimal point between the second and third digits of the hallmark and read off the percent. Therefore, a hallmark of 925 means the objec is 92.5 percent gold and 7.5 percent another metal.

Other Systems

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In the karat system, 24 karats means pure gold. Half gold would be 12 karats and 3/4 gold would be 18 karats. For any system like this, calculate part/whole = hallmark. (The first three digits past the decimal point are the hall mark.) A 15 karat item should be hallmarked 625 because 15/24 = 0.625.