The metric carat is a unit of weight for determining precious stones (1 Kt = 0.2 g), whereas the carat specification for gold alloys defines the fineness of jewelry. The unit of measurement for the metric carat is abbreviated as Kt in Germany (ct is common in Austria and Switzerland). It allows the observer a more precise idea of the value of a diamond, which even experts could not verify with the naked eye. formal dresses online
So two stones sometimes look almost identical on the outside, but differ in their carat number. The specialist measures the true value of a diamond, for example, using the 4cs (English: carat, color, clarity and cut). Of these four, the carat content is the only invisible one as it is determined by the weight of the gemstone. It is only through him that the hidden value of a piece of jewelery is sometimes revealed.
Where does the carat unit of measurement for gemstones come from?
The unit of weight carat was not set to the standardized measure of 0.2 g until 1875. Many centuries before, however, people knew a method for determining the weight of gemstones, which probably laid the foundation for this measuring method: They used the seeds of the carob tree as a counterweight. The croissant-shaped fruits of the carob tree (Ceratornia siliqua) gave the Roman weight unit Siliquia its name. A Siliquia was roughly 189 to 192 milligrams - roughly the weight of our current unit of measurement of one carat. Even the Greeks already weighed their valuable stones in a unit of weight that bore the strikingly similar-sounding name kerat (kerátion = croissant).
How is a gem measured today?
A special carat scale is used to measure a diamond or other precious stones today. This is tested for accuracy before the measurement so that no major deviations can occur (an accuracy of approx. 0.01 to 0.001 carat is normal). In addition to avoiding vibrations, care must also be taken when weighing that heat sources or drafts of air do not falsify the measurement result. Finally, the achieved number of carats is not rounded, unless it is the third 9 after the decimal point (e.g. 0.9990 is given as 1 carat, 2.9989 as 2.99 carats).
Instead of carats, the information is often given in points: 100 points correspond to one carat. A half-carat therefore has a score of 50. Then one speaks of a 50 point or a quarter-carat, for example, of a 25 point. This point is mainly used when the gemstone mass is less than 0.2 g. However, the higher the carat number, the more likely it is that the stone will be referred to as carat.
Carat number: The relationship between value and weight
A popular misconception is that the price of a diamond is directly related to its size. As already mentioned at the beginning, the value of a stone depends on the 4cs: carat, color, clarity and cut. The clarity describes the visibility of occurring shots in the gemstone. Its color can be classified from white to yellowish and increases the value of a diamond the lighter it is. An exception are stones, which shimmer in all colors of the rainbow. These so-called "fancy colored diamonds" also get their color from the special cut. The property of the cut determines the brilliance of a stone. The higher the quality, the more sparkling a wedding ring, for example .
Although there is no direct relationship between size and value of a stone, there is certainly a relationship between its weight and its value. However, the price increase does not take place evenly with the increasing number of carats, instead there are exponential jumps. For example, between a 0.95 carat and a one-carat. This price development is due to the rarity of large diamonds. The higher the number of carats, the more rapidly the price rises; there is a much higher price difference between a stone with three and four carats than between two stones with one and two carats. Nevertheless, caution is advised: Neither the size nor the weight (in Kt) alone determine how valuable the gemstone really is.
The carat and its different effects on a ring
The effect of a valuable diamond results from several factors: the carat weight and its apparent size. However, the human eye tends to distort this second factor. Therefore, the actual dimensions of a diamond are determined with technical aids based on the following factors:
Gemstones can have different depths. The deeper a stone is, the smaller it often appears. In contrast, flatter stones look larger. Here it depends on the viewing angle: Seen from above, a deeper stone looks less large because its weight is in the lower part of the diamond.
2nd cut grade
As already described above, the cut determines the brilliance. This can also hide the real size of the stone, as more light falls back on the eye. A stone with a high carat number can appear smaller if it has a less elaborate cut than its counterpart.
The table is the visible area of the gemstone when viewed from above. If the table is larger, the diamond also appears larger, regardless of whether it is in depth.
If the carat weight of a gemstone is known, there is a relationship between its size in millimeters and the carat in grams:
How do I determine the right carat weight for me?
The easiest way to determine the correct carat weight for your perfect piece of jewelry is to use our wedding ring configurator. Here you can look at the selected ring directly by hand and simply change the size of the diamond. To make it easier to understand, you can see the diameter of each stone in millimeters behind the carat unit. Just click through the different sizes and test their effect on our hand model.
How do you measure the fineness of gold alloys in carats?
The term "carat" is also used to indicate the percentage by weight of pure gold in the total mass of an alloy. Gold alloys are mainly made with copper and silver. The fineness in carats is given in x / 24 parts. One-carat gold therefore corresponds to 1/24 part by weight gold (= 4.167%). One hundred percent purity (24/24) is virtually impossible, since possible impurities can never be completely eliminated. That is why 24-carat gold is said to be 99.99% pure.
Instead of the designation "carat", the purity of gold alloys can also be given in 1/1000 parts. As a result, 24 carat gold would be 999.9 parts. formal dresses with sleeves
The history of the carat term for gold alloys
The history of the carat term for gold alloys also goes back to the Greek and Roman models of the carob tree seeds (see above). In Germany there used to be the carat as a small counterweight that was used to determine the fineness of gold. This weight corresponded to the 24th part of a mark, 1 carat in turn was divided into 12 grän as sub-units. Even today, gold jewelry is still weighed to determine its carat value and thus to make a statement about its fineness. It is important to know that the minimum degree of purity for gold alloys is different in certain countries.