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Distinguishing Between Carats and Karats

Distinguishing Between Carats and Karats

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Distinguishing Between Carats and Karats

In the jewelry world, there's a big difference between carats and karats, but to someone who only hears these terms, they might be perceived as the same. The difference is that carats measure the weight of diamonds and other gemstones, while karats relate to the purity of gold. Here's a look at the differences between carats and karats.

Measuring Diamonds and Gold

A carat, which is often abbreviated as "ct," equals one fifth of a gram, which is commonly referred to as 200 milligrams. Within 1 carat is 100 points, which means a half carat equals 50 points. Keep in mind that a carat is a measurement of weight, not size, as it's possible for gems of the same size to have different carats. Prior to the standardization of carat measurement in 1907, different countries used their own measurement systems to define carat weight.

When evaluating gold, a gemologist measures its purity in karat (K) increments out of 24 parts. That means pure gold is equivalent to 24K, while lower karat values indicate the gold is mixed with a metal alloy. Other types of alloys commonly mixed with gold in jewelry include silver and copper. Traditionally, the term karat has referred to the fineness of gold.

Most gold jewelry, however, is not 100 percent pure, making 24K gold rings extemely rare. In the United States, the most commonly purchased gold jewelry ranges from 10-18K. Modern gold jewelry is usually marked with its karat value.

GIA Tips on Carat Weight

The Gemological Institute of America (GIA) provides authoritative information about various gems and how they are valued. GIA's carat measurements are to the fifth decimal place, whereas jewelers typically list carat to the second decimal. GIA warns consumers not to assume carat width is the same or similar to diamond size.

Another myth jewelry seekers should see through is the notion that a bigger diamond is always better. Of the 4C's (color, clarity, cut and carat), it's up to the buyer to determine how they prioritize these factors to meet their personal tastes. If you're trying to make an investment, it's best to meet with a GIA-certified jeweler who knows both sides of the market.

After a diamond is set, its size and weight can be difficult to estimate with the human eye, since it can be hidden below the girdle. Sometimes a thick girdle can make the diamond seem bigger than it is. Consumers may also get confused about the difference between "carat weight" and "total carat weight" (tcw), which measures the total weight of all the diamonds in a multi-stone ring.


Knowing the difference between carats and karats is essential to becoming a jewelry enthusiast. Understanding how different types of jewelry is valued will help you avoid the traps beginners fall into. Contact us at Ralph Mueller & Associates to learn more about getting the best value for your jewelry.