A carat with a “c” and a karat spelled with a “k” may sound the same but they really have different meanings and refer to different objects. Since both terms refer to items that are used in jewelry making, it causes much confusion to the uninitiated who usually wonders what is a karat. A karat, which usually goes by the abbreviation “kt.” or “k.,” is simply an expression of the purity of gold in a jewelry item. A carat, on the other hand, which is usually abbreviated as “ct.” or “c.,” is a unit of weight by which precious gemstones such as diamonds are measured. A one-carat diamond stone, for instance, is equivalent to one fifth of a gram and can be expressed as 0.20 grams under the metric system. Despite these dissimilarities, the term carat and karat were both derived from the carob beans, which usually have the same size and weight, and were used by the ancient Greeks as a unit of measure for measuring the weight of gold and gemstones.
A karat is made up of 24 units and pure gold is said to be 24 karats. Pure gold is very malleable and can, in fact, be easily hammered into a paper-thin foil or stretched into hair-thin strands without breaking, it is not suited for jewelries if used in its purest form. To make it harder and more durable, other metals such silver, nickel, copper and zinc are usually added to create a gold alloy. When a ring, for instance, is said to be 18-karat gold, it is actually composed of eighteen parts gold expressed as 18/24 = 3/4, or 75 percent gold. While most Americans prefer 14-karat gold jewelries, gold in the United States must be at least 10-karats to be considered as “solid gold.”
When alloyed with silver and copper, gold gains durability and strength without substantially losing its lovely yellow color. However, when other metals are added, the color of gold is somewhat altered. For instance, if copper is added to gold, a gold alloy with a pinkish or rose tint is created. A white gold setting, which complements the brilliance of diamond stones, is created by combining gold with nickel, zinc and copper. Now that you know what is a karat, you can look for the manufacturer’s trademark and karat stamp on the clasp or underside of the jewelry item that you fancy such as bracelet, necklace, ring or earring before you purchase it.