phillip godfrey designer goldsmith
Phillip Godfrey Designer Goldsmith

Diamond: The Four C's

Colour - Clarity - Cut - Carat Weight

Understanding diamonds requires knowledge of the four C’s: cut, colour, clarity and carat weight. It is the interplay of these various characteristics that will determine a stone’s beauty and value.

Diamond cut quality


Many people think of all diamonds as white although they actually vary considerably in colour and in fact most diamonds carry a slight yellowy colour. As well as the more common stones, diamonds can also be found in deeper colours known as fancy colours, although these are very rare. Fancy colours in diamonds include yellow, green, brown, blue, orange and pink.

GIA Color grading scale


Diamond cut is perhaps on a par with clarity as the most important of the four Cs as it can mean the difference between a brilliant diamond and a dull lifeless stone.  


When we speak of a diamond's clarity, we are referring to the presence of identifying characteristics on (blemishes) and within (inclusions) the stone.

If you think about the incredible amount of pressure it takes to create a diamond and the fact that natural diamonds are not grown in a sterile laboratory, it's no surprise that most diamonds have flaws.

Basically there are two types of flaws: inclusions and blemishes. Inclusions refer to internal flaws and blemishes refer to surface flaws. However, in the diamond grades listed below, you'll note that none of the grades include the term "blemish" -- for the purposes of grading diamonds, all flaws are called "inclusions."

Inclusions include flaws such as air bubbles, cracks, and non-diamond minerals found in the diamond. Blemishes include scratches, pits and chips. Some blemishes occur during the cutting processes (most often at the girdle). Diamonds with no or few inclusions and blemishes are more highly valued than those with less clarity because they are rarer.

How are diamonds graded for clarity?

Diamonds are graded for clarity under 10x loupe magnification. Grades range from Flawless (diamonds which are completely free of blemishes and inclusions), to Included 3 (diamonds which possess large, heavy blemishes and inclusions that are visible to the naked eye).

* Flawless: No internal or external flaws. Extremely rare.
* IF Internally Flawless: no internal flaws, but some surface flaws. Very rare.


* VVS1-VVS2 - Very Very Slightly Included (two grades). Minute inclusions very difficult to detect under 10x magnification by a trained gemologist..


* VS1-VS2 - Very Slightly Included (two grades). Minute inclusions seen only with difficulty under 10x magnification.


* SI1-SI2 - Slightly Included (two grades). Minute inclusions more easily detected under 10x magnification.


* I1-I2-I3 - Included (three grades). Inclusions visible under 10x magnification AS WELL AS to the human eye. We do not recommend buying diamonds in any of these grades.


While the presence of these clarity characteristics (inclusions and blemishes) do lower the clarity grade of a diamond, they can also be viewed as proof of a diamond's identity. GIA certificates include what is known as a "plot" of a diamond's inclusions -- think of it as a "diamond fingerprint." Since no two diamonds are exactly the same, comparing the uniqueness of your diamond's clarity characteristics with the plot provided on the diamond certificate offers assurance that the diamond you pay for is the same diamond you receive.

Which Clarity Grade Should I Choose?

While Flawless diamonds are the rarest, a diamond does not have to be flawless to be stunning. In fact, until you drop to the "I" grade, a diamond's clarity grade has an impact on the diamond's value, not on the unmagnified diamond's appearance. Diamonds with VVS and VS grades are excellent choices for both value and appearance. More affordable (and still a great choice) are those diamonds which gemologists call "eye-clean" - diamonds with no inclusions visible to the naked eye. These diamonds are SI1 and SI2 and unless the recipient carries a 10X loupe (a strong jewellery magnifying glass), she won't see the inclusions. As to I1-I3? Maybe when there's a diamond grade that's defined as "you can see the flaws just by looking at the diamond," nothing more needs to be said.

Diamond Cut

First, don't confuse diamond "cut" with "shape." Shape refers to the general outward appearance of the diamond, (such as round, emerald, or pear). When a diamond jeweller (or a diamond certificate) says "cut," that's a reference to the diamond's reflective qualities, not the shape.

Diamond cut is perhaps the most important of the four Cs, so it is important to understand how this quality affects the properties and values of a diamond. A good cut gives a diamond its brilliance, which is that brightness that seems to come from the very heart of a diamond. The angles and finish of any diamond are what determine its ability to handle light, which leads to brilliance.

As shown in the images below, when a diamond is well-cut, light enters through the table and travels to the pavilion where it reflects from one side to the other before reflecting back out of the diamond through the table and to the observer's eye. This light is the brilliance we mentioned, and it's this flashing, fiery effect that makes diamonds so mesmerizing.

Ideal Cut Shallow Cut Fine Cut

In a poorly cut diamond, the light that enters through the table reaches the facets and then 'leaks' out from the sides or bottom of the diamond rather than reflecting back to the eye. Less light reflected back to the eye means less brilliance.

Diamond Anatomy

Wondering what on earth is the diamond's pavillion? Table? Culet? The graphic and supporting text below explain the various "parts" of a diamond.

Fine Cut
  • Diameter - The width of the diamond as measured through the girdle.
  • Table - This is the large, flat top facet of a diamond.
  • Crown - The upper portion of a cut gemstone, above the girdle.
  • Girdle - The narrow rim of a diamond that separates the crown from the pavilion. It is the largest diameter to any part of the stone.
  • Pavillion - The lower portion of the diamond, below the girdle. It is sometimes referred to as the base.
  • Culet - The tiny facet on the pointed bottom of the pavilion, which is the portion of a cut gem below the girdle.
  • Depth - The height of a gemstone, from the culet to the table.

Carat Weight

A carat is a unit of measurement, it's the unit used to weigh a diamond. One carat is equal to 200 milligrams, or 0.2 grams.
Diamond buying guide point: Size does matter. It is not, however, a measure of your love.
iamond buying guide point Keep in mind that differences in size are clearly visible... even to the untrained eye.
The word "carat" is taken from the carob seeds that people once used in ancient times to balance scales. So uniform in shape and weight are these little seeds that even today's sophisticated instruments cannot detect more than three one-thousandths of a difference between them.


The process that forms a diamond happens only in very rare circumstances, and typically the natural materials required are found only in small amounts. That means that larger diamonds are uncovered less often than smaller ones. Thus, large diamonds are rare and have a greater value per carat. For that reason, the price of a diamond rises exponentionally to its size.


There have been many different sets of birthstones used throughout history and in different cultures. This is the list most commonly used nowadays and I invite you to click Belle Moonany of the items below to learn more:-

  1. January - Birthstone Garnet
  2. February - Birthstone Amethyst
  3. March - Birthstone Aquamarine
  4. April - Birthstone Diamond
  5. May - Birthstone Emerald
  6. June - Birthstone Pearl
  7. July - BirthstoneRuby
  8. August - Birthstone Peridot
  9. September - Birthstone Sapphire
  10. October - Birthstone Opal
  11. Novemeber - Birthstone Topaz
  12. December - BirthstoneTurquoise

Care of your jewellery

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