
Carat
(kàr´et) noun
- 1. Abbr. c, car.. A unit of weight for precious stones, equal to 200
milligrams.
- 2. Variant of KARAT.
- [Middle English, from Old French, from Medieval Latin quarâtus, from
Arabic qìrât, weight of four grains, from Greek keration, a weight, diminutive
of keras, horn.]
Webster
Definition for carat
- 1. carat var of KARAT
- 2. car.at \'kar-*t\ n [prob. fr. ML carratus, fr. Ar qi-ra-t bean pod, a
small weight, fr. Gk keration carob bean, a small weight, fr. dim. of kerat-,
keras horn : a unit of weight for precious stones equal to 200 milligrams
Karat
also carat (kàr´et) noun
- Abbr. k, kt.
- A unit of measure for the fineness of gold, equal to 1/24 part. Pure gold
is 24 karat; gold that is 50 percent pure is 12 karat.
- [Variant of CARAT.]
Carat
(F.-Ital.-Arab.-Gk)
- F. carat, a very light weight.
- Ital. carato.
- Arab. qirrat, a pod, husk, carat, 24th part of an ounce.
- Gk. kepatiov, fruit of the locust-tree; also, a carat; lit. 'a
small horn'
- Gk. kepas, stem of , a horn; See Horn.
- A Concise Etymological Dictionary of the English Language, Skeat,
Capricorn Books, 1963 (My embarrassing misspelling corrected by Professor Nick Humez)
Carat weight
- The unit of weight for diamonds and gemstones. It is defined as one-fifth
of a gram (200 milligrams = 0.200 gram). It became legal standard on the 1st
of April, 1914, and was and frequently still is, known as the metric carat.
The old London carat weighed 0.20530 gram, and was not a legal standard and
did not conform to the carat weight in other parts of the world, which varied
in different countries from 0.1885 gram to 0.2135 gram.
- Glossary, Gemmologists' Compendium (6 edition), Robert Webster FGA,
revised by E. Allan Jobbins BSc, CEng, FIMM, FGA, Keeper of Minerals and
Gemstones at the Institute of Geological Sciences (The Geological Museum),
London, 1979.
Weights of carats
(in milligrams) before standardization on the metric carat of 200.0 mg
Alexandria |
191.7 mg |
Frankfurt |
205.8 mg |
Amsterdam |
205.1 mg |
Hamburg |
205.8 mg |
Antwerp |
205.3 mg |
Lisbon |
205.8 mg |
Arabia |
194.4 mg |
London |
205.3-205.5 mg |
Austria-Hungary |
206.1 mg |
Madras |
205.5 mg |
Berlin |
205.5 mg |
Persia |
213.5 mg |
Bologna |
188.5 mg |
Russia |
205.1 mg |
Brazil |
192.2 mg |
Spain |
199.9 mg |
Constantinople |
205.5 mg |
Turin |
213.5 mg |
East Indies |
196.9-205.5 mg |
Venice |
207.0 mg |
Florence |
196.5 mg |
Vienna |
206.1 mg |
France |
205.0-205.5 mg |
Pearl Carat |
207.3 mg |
from Gemstone and Mineral Data Book, John Sinkankas, Van Nostrand Pub.,
1981
Formulas for weights of various gem cuts, with dimensional ratios
Formulas
- So-called "Standard Formulas" for computing the volume of various gem
cuts, sort of a starting point for the
Dendritics Automated Calculations
algorithms.

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