NationMaster - Encyclopedia: Carat (purity)

The carat (abbreviation ct or Kt) is a measure of the purity of gold alloys. In the United States and Canada, the spelling karat is used, while the spelling carat is used to refer to the measure of mass for gemstones (see Carat (mass)). Not to be confused with carrot or caret. ... ... GOLD refers to one of the following: GOLD (IEEE) is an IEEE program designed to garner more student members at the university level (Graduates of the Last Decade). ... An alloy is a combination, either in solution or compound, of two or more elements, at least one of which is a metal, and where the resultant material has metallic properties. ... The carat is a unit of mass used for measuring gems and pearls, and is exactly 200 milligrams. ...

1 Measure
2 Derivation
3 Terminology
4 International caratages of gold jewellery
5 See also
6 Notes
7 References

Measure

As a measure of purity, one carat is $tfrac{1}{24}$ purity by mass:

$X = 24,frac{M_g}{M_m}$

where

X

is the carat rating of the material,

M g

is the mass of pure gold or platinum in the material, and

M m

is the total mass of the material.

Therefore 24-carat gold is fine (99.9% Au w/w), 18-carat gold is 75% gold, 12-carat gold is 50% gold, and so forth.

Historically, in England the carat was divisible into four grains, and the grain was divisible into four quarts. For example, a gold alloy of $tfrac{381}{384}$ fineness (that is, 99.2% purity) could have been described as being 23-carat, 3-grain, 1-quart gold.

The carat system is increasingly being complemented or superseded by the millesimal fineness system in which the purity of precious metals is denoted by parts per thousand of pure metal in the alloy. Millesimal fineness is a system of denoting the purity of platinum, gold and silver alloys by parts per thousand of pure metal in the alloy. ... For the CSI episode of the same name, see Precious Metal (CSI episode). ...

The most common carats used for gold in bullion, jewellery making and by goldsmiths are: A precious metal is a rare metallic element of high, durable economic value. ... For the Korean music group, see Jewelry (group). ... A goldsmith creating a new ring A goldsmith is a metalworker who specializes in working with precious metals, usually to make jewelry. ...

24 carat (millesimal fineness 999)
22 carat (millesimal fineness 916)
20 carat (millesimal fineness 833)
18 carat (millesimal fineness 750)
15 carat (millesimal fineness 625)
14 carat (millesimal fineness 585)
10 carat (millesimal fineness 417)
9 carat (millesimal fineness 375)

Millesimal fineness is a system of denoting the purity of platinum, gold and silver alloys by parts per thousand of pure metal in the alloy. ...

Derivation

The word carat is derived from the Greek kerátiōn (κεράτιων), “fruit of the carob”, via Arabic qīrāṭ (قيراط) and Italian. Carob seeds were used as weights on precision scales because of their reputation for having a uniform weight. However, a 2006 study^[1] by Lindsay Turnbull and others found this to not be the case – carob seeds have as much variation in their weights as other seeds.^[2] In the distant past, different countries each had their own carat, roughly equivalent to a carob seed. In the mid-16th century, the carat was adopted as a measure of gold purity, roughly equivalent to the Roman siliqua ( $tfrac{1}{24}$ of a golden solidus of Constantine I). As a measure of diamond weight, from 1575, the Greek measure was the equivalent of the Roman siliqua, which was $tfrac{1}{24}$ of a golden solidus of Constantine; but was likely never used to measure the weight for gold.^[3] Binomial name Linnaeus The Carob tree (from Arabic: Ø®Ø±ÙˆØ¨ kharoub and Hebrew: ×—×¨×•×‘ Charuv), Ceratonia siliqua, is an evergreen shrub or tree native to the Mediterranean region, cultivated for its edible seed pods. ... Arabic is a Semitic language, closely related to Hebrew and Aramaic. ... Italian is a Romance language spoken by about 70 million people, most of whom live in Italy. ... Julian solidus, ca. ... Flavius Valerius Aurelius Constantinus[2] (27 February c. ...

Terminology

22/22K - a quality mark indicating the purity of gold most popularly used in india. This purity was adapted and practiced by the big jewellers and was latter passed to jewel smiths The first 22 signifies the "Skin purity" of gold jewellery and the second 22 signifies that after melting purity of the gold jewellery will be 22K (22 Karat) or 91.67% of pure gold. This symbol or stamp is very popular on the gold jewellery business in Asian countries like India, Sri Lanka, Pakistan, Bangladesh, Nepal, Yemen, and Persian Gulf countries. GOLD refers to one of the following: GOLD (IEEE) is an IEEE program designed to garner more student members at the university level (Graduates of the Last Decade). ... Map of the Persian Gulf. ...

This practice was pioneered and introduced in the early mid-1980s by Nemichand Bamalwa & Sons of Kolkata, India, sparking a revolution in India as it forced jewellers to indicate correctly the after-melting purity, and heightened consumer awareness made it a most sought-after stamp or quality mark. This article is on Calcutta/Kolkata, the city. ...

Chuk Kam (玉金) – In Cantonese (Chinese) this term means pure gold, literally "Jade Gold". It is defined as 99.0% gold minimum with a 1.0% negative tolerance allowed.^[4]^[5] The quality of gold is guaranteed with a "Certificate of Gold" upon purchases in Hong Kong and Macau.

International caratages of gold jewellery

Region^[4]	Typical Caratage (fineness)
Arabic countries, Oriental East (China, Hong Kong, Taiwan)	24 carat "Chuk Kam" (99.0% min)
Arabic countries, India,Sri Lanka & subcontinent	22 carat (91.6%)
Arabic countries in the Persian Gulf region	21 carat (87.5%), 18 carat (75.0%) in most Egypt
Europe - Southern / Mediterranean	18 carat (75.0%)
Europe - Northern / USA etc	8-18 carat (33.3 - 75.0%)
Russia / former USSR	9 (37.5%) and 14 carat / old 583 and new 585 проба (58.5%)

Arab States redirects here. ... Arab States redirects here. ... Arab States redirects here. ... Map of the Persian Gulf. ... The Mediterranean Sea is an intercontinental sea positioned between Europe to the north, Africa to the south and Asia to the east, covering an approximate area of 2. ... Motto: (traditional) In God We Trust (official, 1956â€“present) Anthem: The Star-Spangled Banner Capital Washington, D.C. Largest city New York City Official language(s) None at the federal level; English de facto Government Federal Republic - President George W. Bush (R) - Vice President Dick Cheney (R) Independence - Declared - Recognized... State motto (Russian): ÐŸÑ€Ð¾Ð»ÐµÑ‚Ð°Ñ€Ð¸Ð¸ Ð²ÑÐµÑ… ÑÑ‚Ñ€Ð°Ð½, ÑÐ¾ÐµÐ´Ð¸Ð½ÑÐ¹Ñ‚ÐµÑÑŒ! (Transliterated: Proletarii vsekh stran, soedinyaytes!) (Translated: Workers of the world, unite!) Capital Moscow Official language None; Russian (de facto) Government Federation of Soviet republics Area - Total - % water 1st before collapse 22,402,200 kmÂ² Approx. ...

Notes

^ Turnbull et al. (2006)
^ New Scientist (2006) — review of Turnbull et al. (2006)
^ Harper, (2001)
^ ^a ^b World Gold Council (2003)
^ Fallon, (2006)

References

Fallon, S. (2006) Hong Kong & Macau, 12th ed., Melbourne; London: Lonely Planet, ISBN 1-7405-9843-1
Harper, D. (2001) "Carat", in: Online Etymological Dictionary, accessed 28 August 2007
New Scientist (2006) Did carob seeds allow shady diamond deals?, New Scientist magazine, 2550 (9 May), p. 20
Turnbull, L.A., Santamaria, L., Martorell, T., Rallo, J. and Hector, A. (2006) "Seed size variability: from carob to carats", Biology Letters, 2 (3: September 22), p. 397–400, DOI 10.1098/rsbl.2006.0476
World Gold Council (2003) The Caratage (Karatage) System For Gold Jewellery, Online article accessed 28 August 2007

Categories: Gold | Gold investments | Precious metals | Units of purity | Jewellery

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Results from FactBites:

Carat (purity) - Wikipedia, the free encyclopedia (152 words)
	Carat is a measure of the purity of gold and platinum alloys.
	Therefore 24-carat gold is pure gold (99.99%), 12-carat gold is 50% purity, etc. In the United States and Canada, the spelling karat is usually used for the measure of purity, while carat refers to the measure of mass.
	The carat system is increasingly being complemented or superseded by the millesimal fineness system in which the purity of precious metals is denoted by parts per thousand of pure metal in the alloy.

Carat - Wikipedia, the free encyclopedia (183 words)
	Carat (mass) is a unit of mass for gems.
	In the United States, carat almost exclusively means the unit of mass.
	Carat (purity) is a unit of purity for gold.

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