What are Gold Karats?
A gold karat is a measurement unit that we use to measure gold's purity.
What is Pure Gold?
Pure gold is composed of 99.95% fine gold and unmixed with any other elements.
Pure gold is too soft to make jewelry, ornaments, art, or coins, so it's usually mixed with other metals to create a gold alloy. Karats indicate how much of your gold is composed of fine gold rather than other metals and impurities.
Looking at the color of your jewelry can give you an indication of what kind of alloy it is. For example, yellow gold is usually pure gold and silver, zinc, or copper. Jewelry marketed as 'rose gold' is pure gold with added copper, giving it its characteristic reddish glow. White gold is pure gold mixed with elements such as platinum, zinc, and rhodium.
How do Karats Work?
Gold karats divide into 24 parts: the higher the number of karats, the purer the gold.
Although it's almost impossible to reach a 100% purity rate, 24K gold is about as close as you can get. 24K gold has a gold purity of 99.95%.
A lower karat number indicates that the alloy contains less gold. 18K gold has 75% gold and 25% other metals.
Why do we use Karats?
Karats were initially used as a measure of gold purity in the Middle Ages with a coin called the mark. A mark weighed 24 carats; this is the same measure we still use today for gemstones. Due to its malleability, gold alone couldn't be used to forge marks, so forgers added different metals to increase its durability.
There's no need to measure the purity of coins anymore because coins are no longer made from gold. However, we still use the karat system today as gold alloys are used most commonly in jewelry.