Pure grown Diamonds

The 4Cs of Diamond Quality

The criteria used to evaluate diamonds as objectively as possible are referred to as the "4Cs".
The 4Cs are the universal method for assessing the quality of all diamonds, everywhere in the world.
The following make up the 4Cs:

The 4 C's
Carat Weight

The size of a diamond is critical to its value. The metric carat, which equals 200 milligrams, is the standard unit of measurement of how much a diamond weighs. Each carat can be subdivided into 100 'points.' This allows for very precise measurements to the hundredth decimal place. A diamond below one carat may be described by its 'points' alone. For instance, a diamond that weighs 0.25 carats is often referred to as a 'twenty-five pointer.' Diamond weights greater than one carat are expressed in carats and decimals. The following abbreviations are used to denote carat weight:

ct. = carat
cts. = carats
cttw = carat total weight
ctw = carat total weight

If other factors are equal, the more a diamond weighs, the more valuable and rarer it will be.


The clarity of a diamond refers to the amount, size, type and location of internal flaws (inclusions) or surface imperfections (blemishes) visible in a diamond using 10x magnification. All diamonds have imperfections in them. The "cleaner" the diamond, the higher the value. The following are the standard grades of diamond clarity:

FL= Flawless -- No inclusions and no blemishes visible under 10x magnification, the most rare and expensive of all clarity grades.

IF= Internally Flawless -- No inclusions visible under 10x magnification, but there may be some tiny external irregularities in the finish.

VVS-1= Very Very Slightly Included 1 -- usually just one tiny inclusion visible only to a trained eye under 10x magnification.

VVS-2= Very Very Slightly Included 2 -- tiny inclusions visible only to a trained eye under 10x magnification.

VS-1= Very Slightly Included 1 -- very small inclusions visible with 10x magnification.

VS-2= Very Slightly Included 2 -- several very small inclusions visible with 10x magnification.

SI-1 and SI-2 = Slightly Included 1 and 2 – noticeable inclusions that are easily seen under 10x magnification.

Many inclusions and blemishes are too tiny to be seen by anyone other than a trained diamond grader. To the naked eye, a VS1 and an SI2 diamond may look exactly the same, but these diamonds are quite different in terms of overall quality. This is why expert and accurate assessment of diamond clarity is extremely important.

The following chart gives some examples of how each grade might look under a 10x loupe:

Clarity Chart for Diamonds

Chart courtesy of International Gemological Institute (IGI)


Grading color determines how closely a diamond's color approaches colorlessness. With the exception of fancy color diamonds, the colorless grade is the most valuable. If a diamond does not have enough color to be called fancy, then it is graded on a scale ranging from Colorless to Light Yellow or "D" through "Z." A "D" color diamond is considered colorless. If the color is more intense than "Z," it is considered fancy. A fancy yellow diamond will sell for a far higher price than a light yellow diamond.

Chart of color diamonds

Chart courtesy of International Gemological Institute (IGI)


Cut or proportion is the only property of a diamond that is totally dependent on human intervention. Diamonds are known for their ability to transmit light and sparkle intensely. Cut is often mistaken for a diamond's shape (round, emerald, pear), but a diamond's cut grade is really about how well a diamond's facets interact with light.

Precise artistry and workmanship are required to fashion a stone so its proportions, symmetry, and polish deliver the magnificent return of light only possible in a diamond.

Cut diagram

Chart courtesy of International Gemological Institute (IGI)