What is the difference between Gold Karat and Carat?
People confuse the words karat and carat. But there is a difference between them. And you should know the difference when buying jewelry.
To clarify, Carat is the unit of weight used for gold, gemstones, and pearls. One carat is set to 200 milligrams or 0.2 grams. So 2 carats of gold equals 400 milligrams of gold (0.4 grams) and 5 carats of gold equals 1g of gold.
Carat is written in short form as C or ct and it does not show purity.
But Karat specifies the purity and fineness. Karat shows the purity of the gold as a proportion to the total weight of the alloy. Based on the gold karat standard, one karat is defined as 1/24th. Thus 10 karat gold (10K gold) means 10 parts gold and 14 parts alloy metals or impurities. Karat is written as K or kt in short form.
To summarize below is gold by karat chart of common gold alloys:
|Common Gold Alloys||Gold Karat||Gold Karat Purity in % (App.)||Millesimal fineness|
|8K||8 Karats||33.3 %||333|
|9K||9 Karats||37.5 %||375|
|10K||10 Karats||41.7 %||417|
|14K||14 Karats||58.33 %||585|
|15K||15 Karats||62.5 %||625|
|18K||18 Karats||75 %||750|
|20K||20 Karats||83.3 %||834|
|21K||21 Karats||87.5 %||875|
|22K||22 Karats||91.6 %||916|
|24K||24 Karats||99.9 %||999|
Why gold jewelry contains impurities?
Because pure gold is too soft for jewelry and can scratch or bend. It will need careful handling and more maintenance than impure gold. So alloy metals or impurities are added to:
- Increase the hardness and durability of the jewelry
- Change its color
- Decrease the cost per unit weight of the jewelry.
Impurities are metals like copper, zinc, nickel, etc.