What is a Carat?

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A number of factors contribute to the valuation of a precious stone. In the diamond business, we commonly refer to these factors as the Four Cs: clarity, color, cut and carat. While the first three are fairly self-explanatory, that last word might leave you scratching your head in the jewelry showroom. So, what exactly is a carat? Let’s take a closer look.

Unit of Measure

A carat is a metric unit of measurement for diamonds and other precious stones. Each carat is equal to 200 milligrams. In the jewelry industry, each carat is subdivided into 100 points, so if your jeweler refers to a 75-point diamond, he’s talking about a stone that weighs 0.75 carats, or 150 milligrams.

What’s In a Name?

According to Etymology Online, the measurement known as a carat has its origins from carato, the Italian word for a carob seed.

As the legend goes, merchants in ancient times noticed that carob seeds were pretty uniform in size and weight, and they were used to balance their scales. Our modern use of the measurement was adopted in the United States in 1913, and now the measurement is universal worldwide.

Not to Be Confused with Karat

You may have also seen the word karat used in terms of jewelry; perhaps you thought it was just a typo or an archaic form of spelling. But karat actually refers to another unit of measurement related to gold.

When spelled with a ‘k,’ a karat is a measurement of the purity of gold. While the precious metal is measured by troy weight and grams, karat refers to how pure it is when alloyed with other metals (24-karat gold is considered as pure as it gets). You won’t see much 24-karat gold, however, since the metal in its purest form is extremely soft.

Remembering the Difference

If you have trouble differentiating the two, keep in mind what we mentioned earlier: Precious stones are judged by the Four Cs – not the Three-Cs-and-a-K. And although a carat is a well-defined measurement, each of the Four Cs has a significant influence on the final price of a stone. Want to learn more? Visit Gemological Institute of America or visit our showroom. One of our gemologists would be happy to explain this in greater detail.

Jeff Johnson & Co. is a full-service jeweler located in Upper Arlington, Ohio. We specialize in custom engagement rings, keepsakes for significant moments, and giving new life to family heirlooms. Our gemologists are trained by the Gemological Institute of America, and they work closely with each customer to ensure that we meet your vision and beyond. Stop by our showroom at 5025 Arlington Centre Blvd. (off Henderson Road), call 614-459-8890, orjjandcompany.com. You can also follow us on Facebook at Jeff Johnson & Co.