Carat or karat What’s the diff

Definition of carat and karat

Most of us guys done have a clue when it comes to buying jewelry as a gift for someone. Sooner or later, someone in your life will put a “BSO” (bright shiny object) on his or her wish list.

Here is some information to help when you make that visit foreign territory known as the jewelry store. It has to do with the difference between the terms carat and karat. Both are relevant, and they are different.

Let’s start with carat with a “c.” A carat (abbreviation ct.) is a weight measurement for precious gemstones, especially diamonds. Many people think the carat refers to the size of the gemstones. That is not complete the case. The carat is a measurement of weight or mass. So, it makes sense that a larger stone would weigh more, thus having more carats. While the weight does affect the size of the gemstones, the carat, along with the purity of the gemstone is what determines the price of the precious stones.

The carat became legal standard for gold on April 1, 1914.

For those who like numbers, a carat is a unit of weight for precious stones, equaling 200 milligrams. To put this in perspective, to have one pound you would need 453 grams, or 453,000 milligrams. Another example is that a person weighing 170 pounds would weigh 385,050-carats.

The “other” karat with a “k”, is used to measure the purity of gold. Gold itself is very soft, and like silver, it needs to be alloyed (combined) with another metal or metals to make it stronger and consequently less expensive.

The term karat comes from the old German gold coin used about one thousand years ago. It was called a mark, and it 24 carats. So the purity of the gold used in this foreign currency many  years ago. The abbreviation for karat is kt.

The fineness of gold uses a unit of measure based on 24 parts. Because of this, the karat is measured by the ratio of gold to the alloyed metal. For example, 18-karat gold is 3/4 gold or 0.750 gold, 12-karat gold is 50 percent pure and 14-karat gold is 14/24 gold or 0.583 gold, etc.

Is 24 karat gold (pure gold) the best quality one can buy? Not necessarily, since it tends to be soft and less durable. It can be susceptible to scratching and can be damaged easily. That is why the gold is combined with metals such as silver, copper and zinc to strengthen it.

Although the karat does determine the value of the gold, it does not tell the price you and I will pay when we go searching for a new BSO. Precious metals are measured in troy ounces with one troy ounce equaling about 31.1 grams. There are 12 ounces per troy pound.

In general, carat refers to mass and karat to refer to gold purity. But, beware that in some places carat is the term compared to both mass and purity..

Also, don’t forget that there is a word caret that refers to spacing symbol or mark used in written or printed material to show the place where something is to be inserted.


This article appeared in the November 25, 2011 Berthoud Weekly Surveyor.


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