Carat (purity)

The carat (abbreviation ct or C) is a measure of the fineness of gold.

Etymology

The carat is a loanword by the French le carat, via Latin means carratus. This originated on the Arabian قيراط / Qirat from the Greek κεράτιον keration ( diminutive of κέρας keras " horn " ), as the fruit ( pod ) of the carob tree is croissant -shaped.

History

In Germany, a small gold weight, the 24th part of a Mark was formerly the carat ( weight unit for determining fineness of gold ). 1 carat usually consisted of 12 Graen as a subunit.

Use

The term carat is used to indicate the purity of gold and indicates how large the proportion of the gold to the total mass of a metal alloy. In this case, gold is mainly processed together with silver and copper.

The gold content in the alloy is given in a 24er - division:

• Einkarätiges gold contains 1/24 by weight of gold ( = 4.166 % or 41.66 ‰) and 23/24 levels of other substances.
• Contains 24 carat gold content ( at least theoretically) 24/24 by weight of gold, and it is impossible for technical reasons, to eliminate all impurities. In practice, therefore, designate the gold content of 99.9 %. This is also called " 999 gold ".

The purity of processed gold can thus be given in 1000 parts. For example, corresponding to 585 gold a gold content of 58.5 % in the metal.

However, please note that this is not the number of gold atoms is meant compared to the number of non- gold atoms in an alloy, but only the mass fraction in relation to the total mass of the alloy. Since gold has a much higher atomic mass ( of about 197 u ) than the usual admixtures ( such as copper, with around 63.5 u), the real part of gold atoms is well below this value.

For example, 333 gold to 333 parts by weight of gold and 667 parts by weight of filler metals ( silver, copper, zinc, tin and other base metals ). The actual amount ratio results now but only from the ratio of the atoms involved. However, due to the much lower atomic mass of filler metals, their share is so large that the number of gold atoms only 15% to 20 % by weight, and not, as seems to suggest the hallmark, 33.3%. For this reason, may 333 gold in many countries are not sold under the name " gold " because this alloy has no gold own property more.

Common fineness

Common fineness in carats of gold are:

In addition, there are many other organizations that are mostly but has fallen into disuse (eg 500) are not used in Germany (eg, 840 in France) or were unable to penetrate the market due to their characteristics (eg. 250).

For Karat gold content, the abbreviation is used frequently kt. Especially with Uhreneinprägungen the abbreviation C is encountered.

The fineness of silver is not given in carats. Instead, there is a 16- part scale was used, the so-called Lötigkeit.