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If 18 carat gold is 75% gold, what is the other 25%?
The Ottawa Mint in Canada is able to produce 99.999% pure gold compared with 99.99% pure gold which many other companies produce.
I think this paragraph should be removed and replaced with a link or reference. To just have the whole excerpt from a legal document copy-pasted, especially if it's this voluminous, seems unacceptable. Or else, have the rest of the entry much more comprehensive (e.g. list the most common gold alloys etc.), so that this huge/bloated copy-pasted paragraph doesn't look too out of place. For instance, information like this one would be perfect for this article: http://www.utilisegold.com/jewellery_technology/colours/colour_alloys/ —Preceding unsigned comment added by 213.243.137.56 (talk) 13:18, 4 April 2009 (UTC)
Any views on this? It is my understanding that the "carat" form is used for mass, and the "karat" form for proportion. In any case, the use in this article is inconsistent.
Carat is a weight measurement used for gems. Karat is a measure of purity used for metals (most common is gold.) As far as the measure of purity is concerned the system is based upon a total of 24 parts i.e. 24K gold is pure gold, 18K is 18parts gold 6 parts other metals (which form an alloy) and so on.... 20:45, 18 September 2007 (UTC)
Agree with Mervyn.
--Caesar J.B. Squitti: Son of Maryann Rosso and Arthur Natale Squitti (talk) 20:37, 8 October 2008 (UTC)
I've worked in the jewelry business for more than a decade now (one compared to my grandfather's eight) and I've never seen gold purity referred to as either 'carat' or ct. Those terms are used pretty exclusively in reference to gem stones, not precious metals. The karat is, and I would need to find some citation on this, an old apothecary's measure as precious metals are weighed by troy ounces which breaks down into 20 pennyweights or dwt. Now there is a difference between the stampings for gold manufactured in the U.S. and that manufactured in European countries. The American system uses the karat value while it's more common to see a decimal stamping such as .585 for 14k or .750 for 18k. Generally when a decimal stamping is used it's used to the thousandth point. The same is used for sterling silver with a 925 stamp that means the silver alloy contains 92.5% pure silver. Platinum is a little different as initially it was stamped as 10% Iridium meaning the alloy was 90% platinum. Contemporary platinum is usually stamped either 900 and 900PT to refer to Iridium platinum or 950 and 950PT to refer to Cobalt platinum which, naturally, is 95% platinum and 5% cobalt. But neither silver or platinum is given a karat value so while this info might be of tangential interest I don't know if it belongs in the article itself. Oh, and as I recall, gold below 10k doesn't have to bear a karat stamping even if it is stamped as gold. Usually you'll see it stamped at 'solid gold'. There's also the stamping for gold-filled items which usually is something along the lines of 1/20 12k gold filled meaning that 1/20th of the total pennyweight of the metal is a 12k gold exterior. (Cosmicomics (talk) 05:25, 6 March 2009 (UTC))
I removed the section below -- probably original research and not relevant since measure by volume is not used. --mervyn 12:45, 23 September 2007 (UTC)
What was removed is downright pedantic - has no bearing or usefullness to anyone in the real world. Gold is alloyed by weight in industry, and the rest is of minor curiousity to the writer, perhaps. In other words, good job, IMO Jjdon (talk) 19:45, 14 January 2008 (UTC)
However, this system of calculation gives only the weight of pure gold contained in an alloy. The term 18-carat gold means that the alloy's weight consists of 75% of gold and 25% of alloy(s). The quantity of gold by volume in a less than 24-carat gold alloy differs according to the alloy(s) used. For example, knowing that standard 18-carat yellow gold consists of 75% gold, 12.5% silver and the remaining 12.5% of copper (all by weight), the volume of pure gold in this alloy will be 60% since gold is much more dense than the alloys used: 19.32 g/cm³ for gold, 10.49 g/cm³ for silver and 8.96 g/cm³ for copper.
This formula gives the amount of gold in cm³ or in ml in an alloy:
where
To have the percentage of the volume of gold in an alloy, divide the volume of gold in cm³ or in ml by the total volume of the alloy in cm³ or in ml.
For 10-carat gold, the gold volume in the alloy represents about 26% of the total volume for standard yellow gold. One should be aware of this, since talking about purity according to weight could lead to some misunderstandings; for many people, purity means volume.
Can someone double-check the data for Russia/former USSR? The typical value cited in the article is 14 karat, and I'm pretty sure that it was and is higher. —Preceding unsigned comment added by 24.4.205.124 (talk) 23:38, 28 September 2007 (UTC)
14KP I was told this was plumb gold very pure. I've never heard of this, does any one know?****
Carmen —Preceding unsigned comment added by 70.234.201.86 (talk) 01:39, 16 May 2008 (UTC)
Yes, I know.
Karat Plumb means that it is EXACTLY what is stamped, and no "allowances" or "plus/minus" tolerances are calculated into its fabrication prior to receiving the KP stamp.
So, as to it being "very pure," that is not quite the case. As to it indicating "very accurate," that would be the more correct definition.
I found another Web site that also described 14-carat gold as 58.5 percent pure; my calculator's telling me it's 58.33 percent. It's not a huge discrepancy, but is one number accepted by industry and one by mathematicians? --Thatnewguy (talk) 16:44, 20 August 2008 (UTC)
The text says, "As a measure of purity, one carat is purity by mass." But the formula shows purity MULTIPLIED by 24, not divided by 24. Is this intentional? --Discostu5 (talk) 22:19, 4 October 2009 (UTC)
The term "karat" is the correct term when measuring gold purity, while "carat" is actually a term to measure the weight of precious stones. 1 Carat = 200 milligrams. —Preceding unsigned comment added by 41.247.103.64 (talk) 11:01, 16 May 2010 (UTC)
In the distant past, different countries each had their own carat, roughly equivalent to a carob seed. In the mid-16th century, the Karat was adopted as a measure of gold purity, roughly equivalent to the Roman siliqua (\tfrac{1}{23} 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]
is it 1/23 or 1/24? — Preceding unsigned comment added by 188.120.133.137 (talk) 10:03, 6 July 2011 (UTC)
Therefore, 24-Karat gold is fine 99.9 ??
Therefore nothing. Per the formula 24 is 100.00%. Of course you then go on the discuss tolerancing and legalities, but it is nonsense to say 99.9 follows from the definition. — Preceding unsigned comment added by 99.56.162.2 (talk) 14:37, 25 February 2012 (UTC)
What is this chart supposed to be saying? Surely all the gold in china isn't 24k. — Preceding unsigned comment added by 99.56.162.2 (talk) 14:44, 25 February 2012 (UTC)
I don't feel the article explains why or how 24 became the number indicating the highest purity. It was the weight of a specific coin in carets? How does that turn into a number and term for purity? Some of the comments here mention alchemists which sounds like a reasonable source for the number, because the might have been into numerology and liked the number 24... but where the 24 came from is the only reason I came to this page, and my curiosity has not been satisfied, so I would really appreciate if someone could add some solid information about that. — Preceding unsigned comment added by 76.195.82.81 (talk) 15:24, 5 December 2012 (UTC)
My guess would be that it's because 24 has a lot of factors, i.e. divides nicely by 2, 3, 4, 6, 8 and 12. Similar reason why 12/24/60 appear a lot in time and the old English imperial system. This is my opinion, I haven't got a reference for it. 62.232.221.250 (talk) 09:21, 10 September 2014 (UTC)
It's pointless to remove it. How much space does that section take on wikipedia's servers? 1kB? Don't give me the usual 'not verifiable' argument. It's basic math for Pete's sake! It enlights people who are concern about how much gold their jewelry contains. Suppose I mix 0.75oz of gold with 0.25oz of lithium, it's 18K thus '75% pure' but hey, there's way more lithium in that alloy than gold. I wouldn't call it 75% pure. Calling karat a measure of purity is misleading and one has to wonder if it's not on purpose because a customer buying gold 10K gold jewelry is probably believing it's 42% pure when in fact, there's much more worthless metals than gold. It should be completly illegal. I wouldn't have bought the jewelry I've bought if I'd knew that information sooner. I feel like I've been scammed. In almost every other aspect of life, we measure purity by volume, not by weight. I cannot believe there's scholarly books in the USA that teach both evolution and creationism when the latter has no scientific evidence, but Wikipedia doesn't want to teach how karats relate to volume. Caveat Emptor : Let the buyer beware. That should be one of the purposes of Wikipedia. — Preceding unsigned comment added by 135.19.198.82 (talk) 03:34, 6 February 2013 (UTC)
It says that karat is to measure the purity of Gold, however, I believe it is also used to measure other things, such as diamond and metals other than Gold. Please correct me if I am wrong, but I believe this is correct. 2001:5C0:1400:A:0:0:0:112D (talk) 17:00, 14 February 2014 (UTC)
24K is (almost) pure gold, but pure gold is soft like butter (or so I've been taught). How is it sold in jewelery that's advertised as 24K? I mean, wouldn't this make the jewelry easily perishable? Ai.unit (talk) 15:35, 24 December 2014 (UTC)