How many carats Gold ?
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). The carat system is increasingly being complemented or superseded by the millesimal fineness system in which the purity of precious metals is denoted by parts per thousand of pure metal in the alloy.
Gold is a chemical element with the symbol Au (Latin: aurum, “shining dawn”) and an atomic number of 79. It has been a highly sought-after precious metal for coinage, jewelry, and other arts since the beginning of recorded history. The metal occurs as nuggets or grains in rocks, in veins and in alluvial deposits. Gold is dense, soft, shiny and the most malleable and ductile pure metal known. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Gold is one of the coinage metals and has served as a symbol of wealth and a store of value throughout history. Gold standards have provided a basis for monetary policies. It also has been linked to a variety of symbolisms and ideologies.
The gold karat ( carat ) system and difference
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 fineness (that is, 99.2% purity) could have been described as being 23-carat, 3-grain, 1-quart gold. 18 carat gold is more popular for gold jewelry with a 75 percent gold and 25 percent other metals ratio, usually silver or copper or a mixture of both.
The most common carats used for gold in bullion, jewellery making and by goldsmiths are:
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)
8 carat (millesimal fineness 333)
1 carat (millesimal fineness 042)
There are several metals used in the creation of fine jewellery. The metal types commonly used to make jewellery include gold, platinum, titanium, silver and stainless steel. Metals including rhodium and palladium are also used with jewellery.
There are several carats available for gold.
The carat is the gold content of the metal. The carat measures the proportion of pure gold mixed with other metal alloy to make up the final metal.
The carat of gold is represented in many countries by the abbreviation ct. Carat can also be called karat, represented by kt or K.
The word carat is derived from the Greek kerátiōn (κεράτιων), “fruit of the carob”, via Arabic qīrāṭ (قيراط) and Italian carato. Carob seeds were used as weights on precision scales because of their reputation for having a uniform weight.(However, a 2006 study by Lindsay Turnbull and others found this to not be the case – carob seeds have as much variation in their weights as other seeds.) This was not the only reason. It is said that in order to keep regional buyers and sellers of gold honest, a potential customer could retrieve their own carob seeds on their way to the market, to check the tolerances of the seeds used by the merchant. If this precaution was not taken, the potential customer would be at the mercy of “2 sets of carob seeds”.
Buying GOLD ?
When trying to decide between the gold carat types there are three things to consider.
- The metals performance with every day wear
- The difference in color between the 9ct, 14ct and 18ct gold
The gold carats normally used in men’s wedding rings are 9ct, 14ct and 18ct.
The higher the proportion of gold used in the final metal, the more valuable and expensive the metal will be. So all other things being the same, an 18ct ring will be more expensive than a 14ct ring and a 14ct ring will be more expensive than a 9ct ring. Many countries only allow certain caratages of gold jewellery to be sold. For example, in the United Kingdom, one can make and sell 9, 14 ,18 and 22 carat gold jewellery but not 12 carat gold as the latter is not a recognised caratage standard by law. In some countries, jewellery lower than 12 carats (50% gold or 500 fineness) cannot be described as gold.
The advantage of making jewellery in caratages lower than 24 ct, apart from price, is the wide range of colour that can be achieved, from socalled green, pale yellow, yellow, rose/pink to red as well as white, depending on the balance of other alloying metals used. The lower the caratage, the wider range of colour is possible (see Colours of Gold). Additionally, properties such as strength and hardness are improved over pure gold, leading to improved wear and scratch resistance and less liable to distortion and damage.
9ct gold contains 37.5% pure gold (375 parts per thousand parts).
14ct gold contains 58.5% pre gold (585 parts per thousand parts).
18ct gold contains 75% pure gold (750 parts per thousand parts).
The remainder of the metals is made up of a combination of alloys, different metals which can help to give the metal its unique appearance, such as a different color.
Other gold carats are used in different parts of the world including 10ct, 22ct and 24ct. It is generally considered that 22ct and 24ct gold are too soft to be used to make men’s wedding rings.
10ct gold (417 parts pure gold per thousand parts) is very similar to 9ct gold and the reason why some countries use 9ct and other countries use 10ct is due to historical reasons, rather than one being superior to the other.
Pure gold (‘fine gold’) is 24 carats (karats) and so 24 carats is theoretically 100% gold. In Chinese, it is also known as “Chuk Kam”, meaning ‘pure gold’ and is defined as 99.0% gold minimum. Thus, there is a 1.0% negative tolerance allowed in this case.
Jewellery is normally stamped with a marking to show the type of gold.
For 9ct gold the stamp will normally be either the number 375, 9ct, 9kt or 9K.
For 14ct gold the stamp will normally be either the number 585, 14ct, 14kt or 14K.
For 18ct gold the stamp will normally be either the number 750, 18ct, 18kt or 18K.
The stamps only indicate the carat of metal. They do not indicate the color of the metal. So for example an 18ct yellow gold ring would have a stamp of 750 as would an 18ct white gold ring.
9ct, 14ct and 18ct gold are each relatively hard and durable metals and are suitable for use in all types of fine jewellery. Gold is also suitable to be used in jewellery that is worn on an every day basis
The Caratage System
Any caratage value lower than 24 is a measure of how much gold there is in the jewellery gold alloy. Thus 18 ct is 18/24ths of 100% gold = 75.0% gold. In fineness terms, this is described as 750 fineness, i.e. 750 parts of gold per thousand parts. The table below gives the various caratages and their equivalent gold content in percent or in fineness terms as recognised by international standards. This is not always exactly the mathematical value! For example, 22 carat is mathematically 22/24ths x 100 = 91.666% but the accepted international standard is 91.60%
Some countries insist that there is no negative tolerance allowed (e.g. UK, where 18 carat is 750 fineness minimum) but in others a negative tolerance, typically 3 parts per thousand, is allowed (e.g. in USA, a fineness of 747 would be accepted as 18 carat). This causes difficulty in the mutual recognition of national marks/hallmarks , a problem raised in the European Union by the Houtwhipper ruling recently. Thus a piece of jewellery assaying at 747 fineness would pass in the USA as 18 carat but fail in the U.KThe difference in price between the gold carats.