Before we understand the difference between 24k, 22k and 18k gold, you must know what karat stands for. Karat is basically a unit used to measure the purity of gold. Due to this, the higher the karatage, the purer the gold. Here’s a simple guide to understanding the difference between 24k, 22k and 18k gold.
24 karat = 99.5% pure gold and above
22 karat = 91.7 % gold
18 karat = 75.0 % gold
14 karat = 58.3 % gold
12 karat = 50.0 % gold
10 karat = 41.7 % gold
In the West the karat is expressed in fineness. For e.g. 24 k gold is expressed as 1000 parts out of 1000 pure or fineness 1.000. 22 k is expressed as 22 divided by 24, multiplied by 1000 which as a result will give you a fineness of 0.9166, 21 karat is 21 divided by 24 multiplied by 1000 which is 0.875 fineness and similarly 18 karat is 0.750 fineness.
18K gold is 75 per cent gold mixed with 25 per cent of other metals like copper or silver etc. Usually studded jewelry and other diamond jewelry is made in 18K gold. Therefore, this kind of gold is less expensive compared to 24K and 22K. This one has a slightly dull gold color.
Recognizing 18K jewelry is rather simple – you will see the item stamped with 18K, 18Kt, 18k or a variation similar to these. Due to this, at times, 18K gold is marked by 750, 0.75 or a stamp similar to these in order to symbolize that the jewelry contains 75 per cent gold.
22K gold jewelry implies that 22 parts of the jewelry amounts to gold and the balance 2 parts are some other metals. This kind of gold is commonly used in jewelry making. In 22K gold, of the 100 per cent, only 91.67 per cent is pure gold. The other 8.33 per cent comprises metals like silver, zinc, nickel and other alloys.
It is this addition of metals that make the texture of gold harder thereby making the jewelry durable. However, you must know that although this can be used to make plain gold jewelry, 22K gold isn’t preferable for diamonds and heavily studded jewelry. 22K gold is always used to make United States gold coins. For the reason that the added metals in a gold coin give the coin durability.
24k gold is also called pure gold or 100 per cent gold. This means that all 24 parts in the gold are all pure gold without traces of any other metals. It is known to be 99.9 per cent pure and takes on a distinct bright yellow color. There is no higher form of gold than 24K and you must be aware of this before you go to a dealer who might tell you that they’re selling you 25K or 26K gold.
Since this is the purest form of gold, it is naturally more expensive than 22K or 18K gold. However, this type of gold is lesser in density as compared to gold of a lower karatage which makes it soft and pliable. Hence, it is not suited for regular forms of jewelry.
In conclusion, coins and bars are mostly bought of 24K gold purity. 24K gold is also used in electronics and medical devices such as those used for children suffering from ear infections who are fitted with gold tympanostomy tubes. This is known to improve aeration of the middle ear.
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