The term ‘Karat’ (or ‘Carat’) is used to describe the purity of gold. Simply put: the higher the karat, the purer the gold.
However, it should be noted that 100% pure gold is so soft that it can be moulded at room temperature, and so, must be alloyed with other metals to be functional as jewellery or bullion such as coins and bars.
Critically, the metals that are used to create a gold alloy will alter its appearance, quality and colour.
See the chart below to learn exactly what degree of gold purity each karat level denotes – the purest being 24 karat.
|99.5% and above
Popular Karat Levels
24k gold, despite being known as ‘pure gold’ is normally never entirely pure. More accurately, it is around 99.9 % pure and therefore takes on the distinctly bright yellow colour of the chemical element (Au), which gives it its name. Given the fact that 24k is the purest form of gold, you should be naturally suspicious of any retailer advertising higher karatage. However, 24k is consistently used in the trade of bullion, bars and coinage that is sold on the retailers listed on this site. Conversely, commercial jewellery is rarely made from such a pure form of gold, given its highly pliable qualities.
22K gold is ideal for high quality jewellery, wherein 22 parts gold are strengthened with 2 parts other metals. Specifically, the additional metals used in the alloy are selected depending on the intended colour and quality of the jewellery piece. For instance, white gold pieces are often alloyed with platinum, whereas rose gold is made by adding copper. However, 22 karat gold is mainly used for plain jewellery, whereas pieces with inlaid precious stones are often with made a less pure variety of the metal for strength purposes.
The most common type of gold used for jewellery and antiques has 18 Karats, due to the versatility afforded by its alloyed metals. Specifically, 18k gold is 75 per cent gold mixed with 25 per cent of other substances, such as silver , copper and zinc. Namely, studded and diamond jewellery is usually made with 18 karat gold, and investors in such expensive pieces should not be put off by what may appear a comparative lack in purity.