When comparing diamonds, one of the first things you’ll hear is the 4C’s of diamonds—Cut, Color, Clarity, and Carat. Out of the 4C’s, a diamond’s carat weight is the most common to consider when comparing one diamonds to another.

What is a carat—is it the same as a karat? Some believe that “carat” and “karat” are one in the same, or perhaps a careless spelling error—but the two terms refer to two entirely separate aspects of a piece of diamond jewelry. Since karat and carat are such common terms in the jewelry industry, you would think more consumers would know what they meant!


Karat Scale


The karat system is used to denote the amount or proportion of pure gold in a particular item out of 24 parts. Though pure gold may seem ideal, it is rarely used in the jewelry industry today as it is exceedingly soft, and therefore not the best option.

Over time, scientists came to discover that by adding other alloys to pure gold, the resulting hybrid retained all of the beneficial characteristics of gold with increased durability over its pure counterpart. Today, the karat system (K) is used to denote the number or parts (by weight) of gold are in a 24-part alloy. For example, 24K (karats) is pure gold, whereas 18K is 18 parts gold and 6 parts metal.


Carat Scale


A Carat is a measurement of a gemstone’s weight, not to be confused with a gemstone’s size. 1 Carat (CT) is equivalent to 0.2 grams, or 200 milligrams, and though two gems may have the same carat weight, due to differences in density they may be two different sizes entirely. A 1-carat diamond for example, would be smaller than a 1-carat emerald, as diamonds are far denser than other gems, and therefore weigh more.

The term “carat” originated in the mid 15th century in the Mediterranean, when gem dealers used carob tree beans to balance their scales when weighing gemstones. Gem dealers chose carob beans as their unit of measurement because carob beans had a uniform size and weight, therefore yielding the most accurate measurements.

As diamond’s carat weight was, and continues to be the most influential factor when determining price, it was imperative that a diamond’s weight be measured as accurately and consistently as possible. The demand for a consistent method of gemstone mass was standardized centuries later in 1907, when the 4th General Conference on Weights and Measures embraced the Metric Carat as the official measurement for weighing gemstones.

Another common misconception is the difference between a diamond’s carat weight and a ring’s total carat weight. Only one out of every thousand diamonds weigh more than one carat, which makes 1+ carat diamonds incredibly rare, driving up the price of such diamonds.

A diamond’s carat weight refers to a specific diamond’s weight (typically the center diamond), whereas a ring’s total carat weight is the sum of the carat weight of all of the diamonds in the ring. For example, some rings may have a number of small diamonds on the band in addition to the center diamond—the ring’s total carat weight is the weight of the center diamond and the smaller diamonds on the band in total.

Though the karat weight of a ring’s metal, and the center diamond’s carat weight are both important factors to consider, the other three of the four C’s are also crucial when comparing diamonds and diamond jewelry. Check back soon for more on the 4C’s of Diamonds, and other important factors to consider when investing in diamond jewelry from your local diamond experts at Charles Schwartz & Son!