"Carat" vs "Karat"
As a child, I often found myself baffled when adults talked jewelry. Where were these mysterious "carrots" they were talking about? And what did a vegetable have to do with gold or diamonds or anything else you'd find in a jewelry store?
I later learned they were actually talking about karats and carats. An honest mistake - these terms confuse many novice jewelry buyers too. Which is which? And what do those karat numbers actually mean?
In the United States, carat (with a c) indicates the weight of a diamond or other gemstone. One carat is equal to 0.2 grams or about 0.007 ounces. Carat gets it's name from the Greek word kerátion, meaning fruit of the carob. In many parts of the world, Carob seeds were once thought to have a uniform weight and were used by merchants as a standard for determining the weight of small items.
In the USA and Canada, Karat (abbreviated as k or kt) describes the purity of gold alloys. Just to confuse the issue, in some countries the word carat (abbreviated ct) is used for both gem weights AND gold purity, but in all the literature on this site, we use North American standards.
So what exactly do those karat numbers mean? When we talk about gold, a karat is one part out of 24. Gold karatage is simply a number which tells us how many 24ths of the metal are actually gold, with 24 karat, or 24 parts out of 24, being pure gold. All other karatages are gold alloys - a combination of pure gold and other metals, typically copper, nickel and/or palladium. For example, 12 karat gold is an alloy in which 12 out of 24 parts are pure gold, or a metal which is 1/2 gold.