Understanding Weight and Purity

The most common weight standard in coins are troy ounces however for certain coins like the Chinese Gold Panda, the taels standard might be used, metric systems like the gram are also occasionally used. The conversion table are as follows:

In the past, the Carat is used to denote the purity of precious metal in a coin*, however this standard is fast being replaced by the millesimal fineness system where the purity of precious metals is denoted by parts per thousand of pure metal in the alloy.

The Carat of a coin is calculated by:

The millesimal fineness system indicate purity by the parts per thousand of pure metal in the alloy. Therefore the most common carats used in gold or platinum converted to millesimal fineness are:

Note that in gemstones, carat is used to denote weight, whereby 1 carat of gemstone is 0.2 grams in weight.