Calculating Karats
The importance of determining gold purity is profoundly understood by the world’s refineries and is the basis for all final gold trade. However, in the field, the actual quantity of gold in a piece of dore (raw gold with some impurities) is difficult to ascertain to anywhere near the degree used by the world’s refineries; accuracy can be off by as much as 10 or 15% in the artisanal mining sector. Purity of gold is most commonly expressed in either percentage (%), as in “five nines gold” being 99.999% gold, or in karats, as in 24 karat gold being more than 99.95% pure. Gold considered London Good Delivered is 99.5%.