Carat (mass)

This article is about the unit of mass used for gemstones and pearls. For the purity scale used for gold, see Fineness § Karat.
carat
A 1-carat (200 mg) brilliant diamond
General information
Symbolct
Conversions
1 ct in ...... is equal to ...
   milligrams   200
Conversions (imperial)
1 imp ct in ...... is equal to ...
   ounces   0.00705
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Diamond-weighing kit, with weights labelled in grams and carats

The carat (ct) is a unit of mass equal to 200 mg (0.00705 oz; 0.00643 ozt), which is used for measuring gemstones and pearls. The current definition, sometimes known as the metric carat, was adopted in 1907 at the Fourth General Conference on Weights and Measures,[1][2] and soon afterwards in many countries around the world.[i] The carat is divisible into 100 points of 2 mg. Other subdivisions, and slightly different mass values, have been used in the past in different locations.

In terms of diamonds, a paragon is a flawless stone of at least 100 carats (20 g).[3]

The ANSI X.12 EDI standard abbreviation for the carat is CD.[4]

  1. ^ Science. American Association for the Advancement of Science. 1908. p. 144. Retrieved 30 June 2012.
  2. ^ Cite error: The named reference CGPM4 was invoked but never defined (see the help page).
  3. ^ American Heritage Dictionary of the English Language. Houghton Mifflin Harcourt. 2013. Archived from the original on 2016-08-09. Retrieved 2013-12-24.
  4. ^ "ANSI Units of Measure" (PDF). das.ct.gov. Dept. of Admin. Services, State of Connecticut. Archived from the original (PDF) on April 17, 2012.


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