The gold’s purity is measured in Karat and mostly categorised as 24, 22, 10, 14, 10 karats. A 24 Karat gold piece is comprised of 100 per cent gold and there is no alloy mixed into it. But ornaments and jewellery can’t be made of 100 per cent pure gold or 24 Karat gold as it is very soft and delicate. Most of jewellery are made of 22 karat to 10 karat of gold. The purity of gold can also be measured in per centages and parts per thousand.
To convert karats into the per centage, you need to divide the karat number by 24 and multiply the result by 100. So, for example, to find out the gold per centage in your 22 karat ring, divide 22 by 24, the result is 0.9166, multiply it with 100, so it equals to 91.66 per cent – that’s the purity of your gold.
Also, an easy way to find out the purity of your gold jewellery is to look for the karat stamp on the jewellery piece. It is mandatory for jewellers to mark Hall Mark and gold karat on each and every gold piece.
So, if your gold chain has “18K” marked onto it, this means that piece contains 18 parts gold and 6 parts of other metals. You can also convert this karat value into per centage with above-mentioned formula. It should come to 75 per cent gold content.
Here are some of the frequently used karat marks and their corresponding percentages with respective parts-per-thousand values:
24K – 99.9% (999)
22K – 91.7% (917)
20K – 83.3% (833)
18K – 75.0% (750)
14K – 58.3% (583)
10K – 41.7% (417)
Courtesy : timesofindia.indiatimes.com