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The Coin Geek

Scrap Gold Jewelry Purity Math

Gold jewelry comes in many different purities. These are often referred to as ”karats”.

The standard in Gold is 24 karat. This is pure gold, without imperfection or alloy. Gold is measured in Troy Ounces, so there is 31.103 grams in an ounce (we’ll use 31.1).  Any time you want to figure the purity of gold you divide the karat purity by 24. For example – 18k is 75% pure (18/24=.750). The chart below gives details to the rest of the normally seen purities.

These numbers will help you know how much gold you have in your jewelry and gold items. If you have other questions on gold just give us a call. We also buy gold jewelry by the karat weight. 520-881-7200.

Karat
Purity
Grams : Pure Ounce
 
Comments
24K 100% 31.10g This is pure gold!
22K 91.7% 33.91g Most Far East countries prefer 22-24K gold for jewelry.
21.6K 90% 34.56g

90% Gold Stamp on Ring.

Many coins are 90%. This karat weight is not usually used in jewelry…unless it is made from a coin!
18K 75% 41.47g

18k Gold Stamp

Often used in high end and custom jewelry.
14K 58.5% 53.16g

14k GOLD Stamp Back of Watch.

This is the most common karat weight for jewelry.
10K 41.6% 74.75g

10K Gold Ring Stamp.

In the US 10K is becoming the most commonly used weight as many jewelry stores try to lower their costs.
9K 37.5% 82.93g Scarcely seen. Mostly in 19th century Western Europe and UK.
8k 33.3% 93.3g Sometimes used in 19th century Mexico and UK.

 

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