Jewelry Articles

The 4 C’s Of Diamond Grading

August 15, 2017 - Jewelry Articles
If you have ever bought or sold a diamond, you will likely have heard the term “the 4 C’s”. But what exactly are the 4 C’s and why are they important? In this article, we will take a closer look at the 4 C’s and answer the following questions:

  1. What is diamond grading?
  2. What are the 4 C’s?
  3. How do the 4 C’s affect the price of a diamond?
  4. How do you find out the 4 C’s of a diamond?
  5. How can I find out how much my diamond is worth?



Diamond grading is the act of assessing a diamond and grading it according to industry set diamond standards. When grading a diamond, a gemologist will first establish the 4 C’s of the stone. While these are not the only factors that affect diamond price, they are arguably the most important. Diamond grading laboratories such as the Gemological Institute of America (GIA), will then issue a diamond certificate that detail the characteristics of the stone.

grading a diamond


  1. Carat Weight
  2. Color Grade
  3. Clarity Grade
  4. Cut Grade


Let’s begin by going through each C that affects a diamond’s value:

  1. Carat Weight


Carat weight, also abbreviated to ct, is the standard unit of measurement for diamonds and gemstones. The term carat comes from carob seed, a seed so uniform in weight (approximately 0.2g) that it became a popular unit of measurement in ancient times.


A carat weight is measured to the thousandth of a carat and rounded to the nearest one hundredth. Our Diamond Weight Calculator allows you to determine the carat weight of your diamond.


  1. Color Grade

White diamond color grades range from D (colorless) -Z (tinted yellow or brown) . The more colorless the diamond, the more valuable it is. D color diamonds fetch more than Z diamonds as a poor color grade is low in demand, which deflates its value in the market.

Color Grade
D-F Colorless
G-J Near Colorless
K-M Faint (Slight visible tint)
N-R Very light (More visible tint)
S-Z Light (Noticeable yellow or brown tint)

The color grading scale for diamonds starts with the letter D and not the letter A, as diamond color was previously graded using the letters A-C (sometimes using multiple letter A’s), Arabic numbers (0, 1, 2) and Roman numerals (I, II, III). In order to avoid confusion and create a brand new color grading scale, the GIA chose the D-Z scale


  1. Clarity Grade

Clarity grade refers to the presence, or lack of, external and internal flaws. Flawless diamonds are rare and more expensive than flawed stones. Clarity grade ranges from IF (internally Flawless) to I3. Many flaws are not visible to the naked eye but have to be examined under a loupe.

Clarity Grade
FL Flawless (No flaws externally and internally)
IF Internally Flawless (No flaws internally but some flaws externally)
VVS1, VVS2 Very, Very Slightly Included (Slight internal flaws)
VS1, VS2 Very Slightly Included (Slightly internal flaws but cannot be seen by the naked eye)
SI1, SI2 Slightly Included (Slight internal flaws that may be seen by the naked eye)
I1, I2, I3 Included (Flaws that are visible to the naked eye)


  1. Cut Grade

Cut grade is how well a diamond can transmit light. This depends on its proportions (table, width, depth), symmetrical facets (girdle, pavilion, table, culet), polish (final treatment), brilliance (strong brightness & contrast), fire (distribution of colored light), scintillation (sparkle). Besides affecting a diamond’s value, the cut grade is also essential in determining its sparkle. Cut grades range from Excellent to Poor.

Cut Grade
Excellent Maximum polish, symmetry, brilliance,  fire, and scintillation
Very good Much of the light is appropriately reflected
Good Light is properly reflected but the fire and brilliance are not intense
Fair Light escapes, and the fire and brilliance are quite dull
Poor Diamond appears dull with the light escaping the stone

4 c's


Carat weight: the price-per-carat of a stone increases as the weight increases. The larger the carat weight of a diamond, the larger it appears in size. There are certain “magic numbers” when it comes to carat weight, for example a 1ct is worthy significantly more than a 0.99ct diamond of the same quality. The same is true of a 2 ct vs a 1.99ct and a 3ct vs a 2.99ct and so on.


Color grade: the closer the diamond to a D grade, the greater its value. As mentioned above, the grading system ranges from D-Z with D (colorless) being the best color grade and Z (yellow tint/brown) being the worst. While a diamond may appear to be completely colorless, most diamonds do have a hint of yellow upon closer inspection and close comparison to other diamonds.


Clarity grade: the more flawless the diamond, the more valuable it is. However, just because you cannot see any eye visible flaws, does not mean that the diamond is flawless. Many flaws are only visible under a loupe.


Cut grade: ranging from excellent to poor, a good cut grade will increase the value of a diamond . In some situations, a diamond may undergo a re-cut to earn a higher cut grade. However this will mean losing some carat weight.


Most diamonds come with a grading report coming from certified laboratories such as the Gemological Institute of America (GIA), American Gem Society (AGS), European Gemological Laboratory (EGL), and International Gemological Institute (IGI). Not all laboratories are the same however. The GIA is widely recognized as the most accurate and trustworthy of diamond grading entities. Some laboratories do have a history of inflating the grades and providing certificates of varying accuracy.



Most jewelers offer an appraisal service for a fee. However this will simply detail the characteristics of your stone, it will not enable you to ascertain its resell value.

A few things to remember:

  1. Insurance or appraisal values are extremely inflated and not representative of a diamonds’ value on the secondhand market.
  2. The resell value of a diamond is typically 25%-45% of what was paid at retail.

If you are looking to sell your diamond for a competitive price with no fees involved, WP Diamonds is your solution. A leading online diamond buyer, we offer a fast and safe selling experience; with GIA trained gemologists on hand to examine your diamond and make you a cash offer. Simply fill out the online form to receive your price quote.

Bio: Written by one of our diamond, designer jewelry or luxury watch experts. With over 150 years of combined experience, our experts are able to comment on trends, share industry knowledge and provide diamond, designer jewelry and luxury watch education.

What To Do Next

Related Articles
Diamond Articles: Diamond Clarity 

In this article, we will answer the following questions about diamond clarity: What is diamond clarity? How is diamond clarity graded? How will diamond clarity affect my diamond’s value? What types of inclu...


Diamonds come in an array of dazzling colors. Along with cut, clarity, and carat weight, color is one of the 4 C’s of diamond quality and is an important attribute for assessing your stone. Color has a signi...


Definition: Diamond cut refers to how well a diamond interacts with light. Cut grade is determined primarily by the symmetry, proportions, and polish of a stone, not its shape. Along with color, clarity, and c...


Whether you are looking to buy diamonds or sell diamonds, understanding carat weight is key. Along with color, clarity, and cut, carat weight is one of the 4 C’s that determines diamond quality. Across the i...

We guarantee the safety, security, and privacy of your valuables

We're Proudly Accredited By

Better Business Bureau Logo
  • NPA Logo
  • JVC Logo
  • Better Business Bureau Logo
  • Jewelers Board of Trade Logo