Without being a jewelry industry expert, the jumble of industry specific terms you encounter while shopping for engagement rings, eternity rings or other jewelry can make your search for the perfect piece seem daunting. What do these terms mean? How do you know you are purchasing the quality of jewelry you desire? Perhaps one of the more common questions that arises is the difference between a carat and a karat. Though these terms are pronounced the same and are both used in the jewelry industry, they do in fact have different meanings.



Generally speaking, a karat is unit of purity, while a carat is a unit of weight used to describe gemstones. A common mistake is using the terms interchangeably, under the assumption that a carat is a karat is a carat. Let’s examine in further detail what each term means in order to gain an understanding of the difference.

More about the karat:

You have probably heard the term karat in reference to gold. A karat is often represented by the abbreviation k. or kt. Due to its softness as compared to other metals, gold is often mixed with another metal or metals to create more durable and less expensive jewelry. One karat represents 1/24th of the whole, that is to say that 24 karat gold is pure gold. Any karat designation less than 24 conveys that the gold is combined with other metal(s), creating an alloy. Gold designated as 18 karat gold consists of eighteen parts gold and six parts other metal, for total of 24 parts. Likewise, gold designated as 14 karat is comprised of fourteen parts gold and ten parts other metal. Ten karat gold, containing ten parts gold and fourteen parts other metal, represents the minimum karats which may be deemed “gold" in the United States.

More about the carat:

A carat, abbreviated c. or ct., on the other hand, is a unit used to measure the weight of diamonds and other gems. One carat is 200 milligrams, or 1/5th of a gram. Note that the carat designation refers to the weight of a gem, not its physical size. Thus, one carat of a denser gemstone would appear smaller than one carat of a less dense stone.

The terms carat and karat are believed to be derived from the carob bean, which is a seed pod exhibiting such consistent weight that it was historically used to measure the weight of gemstones.