The Difference Between Carats and Karats

Some things in the jewelry world are easy and well thought-out, and then we have the measurement system. Often asked is the difference between a carat and a karat.

While neither of these are a vegetable, they are both vital measurements that help determine the worth of a certain stone or metal. In fact, that’s the major difference: carats measure the weight of precious stones such as diamonds, while karats measure the purity of a precious metal such as gold.

Quick and Dirty

Without diving too far into detail, carats are used as the major measurement in pricing precious gemstones and, especially, diamonds. Typical carat range is anywhere from 0.2 carats to 5 carats, with most people settling just below 1 carat. Anything above 5 carats, while magnificent, can start causing other effects. To put it simply, you don’t want to walk into a bad part of town with a 10 carat ring on. For this measurement, carat is typically spelled out and not abbreviated.

Karats on the other hand are abbreviated as ‘kt’ and represent the percentage of a metal that consists of gold. If a precious metal is 9kt, or 9 karats, it is just over 37% gold. If it’s 24kt then it’s just shy of 100% gold.

Pure or Impure?

One common confusion with the gold measurement comes at 24 karats. 24 karats means that the gold is 99.9% pure. You might be thinking “great, what’s the difference between that and 100%” and you’d be right in most situations. However, there are several grades above that. These are generally refined in Mints. Grades include 99.99, 99.999… well, you can see where this is going. These numbers are important for things such as buying gold bars (which print the purity directly on the bar), but when it comes to jewelry you’re not going to care too much beyond 24 karats.

Oddly enough, there is no such thing as 100% pure gold. In fact, there is no metal on earth that is 100% pure. The reason for this is that contact with Oxygen causes metals to oxidize. Perhaps there’s some weird scenario where we could get 100% pure gold in outer space, but it wouldn’t be worth the hassle. Additionally: the higher the karats, the softer the gold. For this reason, gold jewelry cannot be made out of 24kt gold. 22kt is the maximum and is generally considered non-ideal.