What is a Carat?

A carat is a unit of measurement used to express the weight of precious stones. The word comes from the Greek name for the carob or locust tree. The dried seed of this tree was originally used by gem traders as the unit for weighing their gems. Because the seeds are not perfectly uniform, variations in the value of the carat developed in different areas. An international or metric carat of 0.2 grams (1 gram equals 0.035 ounces) was proposed in Paris in 1907. This value was adopted by the United States in 1913, and it is now generally accepted in most countries. One carat is equal to about 3.086 grains in the troy system.

The word "carat" is also used to express the purity of gold; in this sense, it is usually spelled karat. A karat is not a unit of weight but instead means 1/24th part. Thus, 24-karat gold is pure gold, whereas 18-karat gold contains 18 parts gold and 6 parts alloy.

More by this Author

  • Machine Tools
    6

    Machine tools are vital to modern technology, for they are capable of shaping metal to the precise dimensions required by the system of mass production and interchangeable parts. Machine tools are applied to metal...

  • Oceanic Art
    1

    Also called the South Seas, Oceania covers all the islands of the South Pacific, including New Guinea, New Zealand, Hawaii and Easter Island. Oceanic art is divided into three subdivisions corresponding to the three...

  • Everything You Ever Wanted To Know About Poop
    21

    Poop aka Stools aka Feces. This is the term applied to the discharges from the bowel. They are also referred to as "motions."


Comments

No comments yet.

    Sign in or sign up and post using a HubPages Network account.

    0 of 8192 characters used
    Post Comment

    No HTML is allowed in comments, but URLs will be hyperlinked. Comments are not for promoting your articles or other sites.


    Click to Rate This Article
    working