What do you mean by the “4 C’s”?

Each diamond can be assigned individual characteristics - similar to a human fingerprint. These properties are known as the 4C's, which stand for Carat (weight), Clarity (purity), Cut (cut quality) and Color (color). They serve as globally recognized standards for assessing the quality of diamonds.

An example: The size of the stone alone says nothing about its value. A large stone that has imperfections (also known as inclusions) is less valuable than a small stone that is flawless.

These evaluation criteria apply to mined diamonds as well as to diamonds grown in the laboratory, so-called lab grown diamonds, which we use for our jewelry.

Would you like to find out more about the difference between classic mined diamonds and innovative lab grown diamonds? You can find more information in this blog article.

The definition of the C's


Carat, or “Karat” in German, indicates the weight of the diamond, with 1 carat equaling 0.2g. The weight can be used to roughly determine the size of the stone, because the proportions of different diamonds with the same cut are almost the same. There is also the option of certification, although this only makes sense for stones with a carat weight of 0.23g or more, as the costs for the assessment are no longer proportional for smaller stones. It should also be noted that the institute that evaluates the diamonds should always be independent, neutral and professional in order to be able to correctly determine the quality and therefore the value of the diamond. Recognized gemmological (gemological) institutes include, for example, the GIA (​​Gemological Institute of America) or its European counterpart HRD (Hoge Raad voor Diamant), which means High Council of Diamonds .


The degree of purity is defined by the term Clarity. During the formation of diamonds, a chemical process that occurs in nature in which extremely hot temperatures and carbon atoms interact, it can happen that other minerals are also included in the diamond and the structure is thereby disturbed and does not appear completely clear. These inclusions reduce the value of a stone. Absolutely pure diamonds are extremely rare and therefore even more valuable.

The GIA has defined a clarity scale that includes 11 levels, with most diamonds falling into the VS (very slightly included) or SI (slightly included) categories.

  • Flawless (FL) = Flawless: No inclusions or blemishes are visible at 10x magnification
  • Internally Flawless (IF) = Internally flawless: no inclusions; Blemishes are only visible under 10x magnification
  • Very, Very Slightly Included (VVS1 and VVS2) = Very, very slightly included: inclusions are difficult to see under 10x magnification
  • Very Slightly Included (VS1 and VS2): Inclusions are minor but are easier to see under 10x magnification
  • Slightly Included (SI1 and SI2) = Slightly included: inclusions can be seen under 10x magnification
  • Included (I1, I2 and I3) = Included: Inclusions are visible under 10x magnification and with the naked eye and can affect the transparency and brilliance of the diamond


The cut quality, or cut, is the most important characteristic in determining the brilliance of a diamond. It should be noted here that it is not the cut shape (i.e. round or square, princess cut, etc.) that is evaluated, but rather the actual quality of the cut. When the height and width of the diamond are in the right proportion, the stone reflects the light back to the viewer, creating the desired “inner fire” - which means a very well cut diamond. Poorly cut diamonds sparkle less because they scatter light in all directions due to small inequalities. The arrangement of the facets is also very important - when they are coordinated with one another, a calm image emerges when viewed from above. The subsequent polishing, which is usually only visible through a magnifying glass, should not be ignored - the fewer grinding marks the better, ideally none are visible at all.

Even though the focus of this feature is on the quality of the cut, the cut shapes should not be completely ignored. The most popular facet cuts include the baguette cut, the brilliant cut, the heart cut, the oval cut, the cushion cut, the princess cut, the emerald cut and lastly the pear cut.



Color is one of the most important factors in determining quality. A distinction is made here between colorless diamonds and diamonds that have a yellow tint. The colorless (or very fine white) diamonds represent the best quality and are therefore the most valuable. Here, too, there is an internationally valid rating scale that the GIA developed. It ranges from the top quality (color D) to the recognizable tinted color Z. In a somewhat rougher division, the individual letters are combined into six groups:

Very fine white (D and E), fine white (F and G), white (H), slightly tinted white (I and J), tinted white (K and L); the remaining levels up to Z are given the designation tinted or clear tint.


But there are also diamonds that have a completely different color - namely pink, red, yellow, green, brown or black. They are called “fancy diamonds”, are very rare and in most cases more expensive than white diamonds. Our own evaluation criteria are used to determine their quality.

Sources (as of August 26, 2022)