Understanding Gold Purity: 9K, 10K, 14K, 18K, 22K, and 24K

Posted by VytarsJewellery on

Many of us, at one point or another, will shop for gold in the jewelry department of a department store or in a jewelry store.

If you've ever gone shopping for jewelry, you are probably familiar with the word “karat” as applied to gold. The higher the karat, the more expensive it will be. But have you ever wondered why? The short answer is that higher karats mean more gold, but there’s more to it than that.

What does it all mean? And what is all of that fine print stamped into your piece of gold? What are karats really? How do you know how pure that gold really is? This article will answer these questions and more.

What Are Karats?

Karats, spelled "carats" outside of North America, are the little numbers stamped on a piece of gold in the format of "xxK" or "xxKT". The numbers refer to the type of gold and to the actual gold content in the particular piece of jewelry.

Here’s more information on karats:

  • Karat is a measurement of the ratio of gold to other metals or alloys.
  • Karats are measured on a scale from 0 to 24.
  • The higher the karat number, the more gold there is and the less other metal content.
  • Other metals and alloys could include copper, nickel (not common anymore), silver, or palladium.

With this in mind, 24-karat gold is the purest gold you can buy.

Why Are Other Metals Added to Pure Gold?

Gold is malleable in its pure state. Other metals are added to strengthen it and in some cases to enhance color. An example is "rose gold" comprises gold and copper.

How to Use Karats to Measure Gold Purity

Knowing the number of karats is key to calculating the gold content on your own. Here is how to use the number of karats to figure out how pure your piece of gold is.

Say you purchase a ring that is 14K gold. Since the number amount of karats you can have is 24K, divide the 14 Karats by the 24. You will get .583. This means that the gold is 58.3% pure.

Gold Purity Conversion Chart

Number of Karats Parts of Gold % of Gold Purity Millesimal Fineness

9K

9/24

37.5

375

10K

10/24

41.7

416/417

12K

12/24

50.0

500

14K

14/24

58.3

583/585

18K

18/24

75.0

750

22K

22/24

91.7

916/917

24K

24/24

99.9

999

As you can see in the above chart, "millesimal fineness" refers to the percent of gold, while karats refer to the ratio of gold to other metals in the piece. Converting between the two is rather easy when you convert the percent to fraction form, or vice versa.

Does High Karat Mean Higher-Quality Gold?

Purer gold does not mean better, it means more pure, worth more money, and more expensive. With gold, the phrase “less is more” can certainly apply. As stated earlier, the less pure the gold is, the more alloy metals it contains. Gold that is blended with more alloys is stronger. This may be preferable especially for jewelry as 24K gold is very soft and not as durable. The lower the karats in a ring, the stronger it will be. Let’s compare lower and higher karats:

  • The lower the karat, the stronger it will be, while higher karat gold will be softer.
  • Lower karat gold is not tarnish-resistant. Higher karat gold is much more resistant to tarnishing.
  • Lower karat gold is not worth as much monetarily. Higher karat gold is more valuable because it is purer.
  • Higher karat gold will appear more yellow.

Choose the purity level that makes the most sense for what you intend to use it for, whether you will subject it to a lot of force, and your personal preferences