A Beginner’s Guide to Understanding the 4C’s

A Beginner’s Guide to Understanding the 4C’s

Being familiar with the 4C’s enables you to talk about a diamond’s quality in a ‘universal language’, and helps you understand exactly what type of diamond you are about to purchase.


Many people confuse the colour grade of a diamond with the category of diamonds that are referred to as fancy coloured diamonds—diamonds that are naturally-coloured.

This is not what we are referring to when we talk about ‘Colour’ in the 4C’s.

When talking about Colour in the context of the 4C’s, we are actually talking about a diamond’s lack of colour. The less colour, the better the diamond.

Diamond colours are sorted into five different grades:



The best diamonds are those that are colourless. These have a grading of ‘D’, ‘E’ or ‘F’. They are significantly more expensive. The differences between these three grades is very small, and all three grades are considered to be a high-grade colour. These diamonds look excellent when paired with white gold or platinum ring metals.

Near Colourless


The next best, are diamonds that are near colourless. These have a grading of ‘G’, ‘H’, ‘I’ or ‘J’. Near colourless diamonds are more common than colourless diamonds, and are therefore less expensive. These diamonds have either a very slight warmth to their tone, a faint yellow hue, a slight yellow tint or a light yellow tone. All of these features are difficult to detect by the naked eye and can typically only be seen when compared side-by-side with diamonds of a higher colour grade.

Faint Colour


Following on, are faint colour diamonds. These have a grading of ‘K’, ‘L’ or ‘M’. These diamonds are a good option if you desire a larger diamond, but are limited by budget. Their faint colour is often hard to differentiate from lower-grade, near colourless diamonds.

Light Colour


After this, are light colour diamonds. These have a grading of ‘N’, ‘O’, ‘P’, ‘Q’ or ‘R’. These diamonds have a slight colour that can be seen by the naked eye. They are much cheaper than higher-grade diamond colours, and are usually deemed undesirable because of their inferior qualities.

Very Light Colour


Finally, there are very light colour diamonds. These have a grading of ‘S’, ‘T’, ‘U’, ‘V’, ‘W’, ‘X’, ‘Y’ or ‘Z’. These diamonds have a warm tint that is visible to the naked eye. They are generally deemed undesirable for making jewellery and are rarely used when making diamond engagement rings.


Diamond Clarity refers to the absence of blemishes and inclusions.

Flaws on the surface of the diamond are referred to as blemishes. Flaws within the stone are referred to as inclusions.

Since diamonds are natural creations—created over millions of years—inclusions and blemishes are inevitable. Nonetheless, diamonds with the fewest inclusions or blemishes receive the highest clarity grade, and have a higher value.

There are different types of diamond inclusions and blemishes. Examples of diamond inclusions are clouds, feathers, knots and internal graining. Examples of diamond blemishes are polish lines, scratches, nicks and breaks.

There are five factors when it comes to determining a diamond’s clarity:


  1. Size: The larger or more noticeable the flaw, the lower the clarity grade
  2. Number: The fewer flaws, the higher the clarity grade
  3. Position: The location of flaws has the potential to turn inclusions into reflectors, which will lower the clarity grade
  4. Nature: The type of inclusion and its impact on the diamond’s durability will influence the clarity grade
  5. Relief: The contrast between the flaw and its surrounding area will influence how easily the inclusion is able to be seen, and will impact the clarity grade

There are six different diamond clarity grades on the GIA scale:



These are diamonds with no blemishes or inclusions that are visible under a 10x magnification. They are incredibly rare and represent less than 1% of all diamonds.

Internally Flawless


These are diamonds with no inclusions within the stone that are visible under a 10x magnification. They have small surface blemishes that are visible under a microscope, but still remain eye clean.

Very, Very Slightly Included


These are diamonds with no inclusions within the stone that are visible under a 10x magnification. They have small surface blemishes that are visible under a microscope, but still remain eye-clean.

Very Slightly Included


These are diamonds with no inclusions within the stone that are visible under a 10x magnification. They have small surface blemishes that are visible under a microscope, but still remain eye clean.

Slightly Included


These are diamonds with minor inclusions that range from difficult through to somewhat easy to see at 10x magnification.



These are diamonds with inclusions that are noticeable under a 10x magnification. They are not always eye clean.

Usually, a diamond’s beauty is not affected by any inclusions since most inclusions can only be seen under a magnifying glass. This makes diamond clarity less important than a diamond’s colour or cut.

For this reason, Slightly Included (SI) and Very Slightly Included (VS) graded diamonds often provide the greatest bang-for-buck since any inclusions are almost impossible to be seen without magnification.

Clarity becomes more important for diamonds with a larger carat weight, and with some fancy-shaped diamonds that accentuate flaws.


It’s a common misconception that when talking about a diamond’s cut, we’re talking about its shape (e.g. round, heart, pear, etc).

Cut actually refers to how well a diamond’s facets interact with light to create sparkle and brilliance.

Of all the 4C’s, a diamond’s cut is the most complex and has the greatest impact on its…


  1. Brightness:The amount of internal and external white light that is reflected from the diamond
  2. Fire:The scattering of white light into a broad range of colours
  3. Scintillation:The amount of sparkle a diamond produces and pattern of light vs. dark areas resulting from reflections within the diamond

A well-cut diamond also reflects the design and craftsmanship that went into producing the diamond. It includes features such as the diamond’s weight-to-diameter ratio, girdle thickness, symmetry of its facet arrangement and quality of polish on all its facets.

In simple terms, the cut grade of a diamond refers to its light performance, meaning the degree to which the diamond retains and reflects the light that enters it. A diamond with a good cut will be highly reflective and exhibit the best possible amount of sparkle. Conversely, diamonds that ‘leak’ light through the bottom or side are usually cut too shallow or deep, and will thus have a less favorable cut grade.

Hence, it is the cut of a diamond that affects the way that light travels through the gem, how much is reflected in the eye, and how much leaks out the back.

A well-cut diamond gives off more bright sparkle and shine, and is therefore more highly valued. A diamond that is cut poorly or too thin will have a lot of light leakage, eliminating its potential for sparkle, and diminishing its value. It takes great skill and craftsmanship to transform a diamond in the rough into a dazzling gem.

The Gemological Institute of America (GIA) have created an objective rating system that is widely-accepted as the gold-standard for evaluating a diamond’s cut.

GIA breaks a diamond’s cut down into five categories, and grades a diamond based on the amount of light it is able to refract back out of its table:


The best possible rating is Excellent, and this signifies the diamond is refracting the highest potential amount of light, thus creating an exceptional shimmer when viewed.

Very Good

Next, there is a Very Good cut, which is not an optimal cut, however, it is well-above average and provides a great combination of light refraction and value.


Following closely behind is the Good cut, which produces an adequate amount of brilliance; however, it shimmers noticeably less than the excellent and very good cuts.


Next, the Fair cut provides an acceptable amount of shimmer but is significantly less shiny than the aforementioned cuts.


Last is the Poor cut, which produces a base level of shimmer and should be taken out of consideration if at all possible.

Carat Weight

The term carat is also often misunderstood. It refers to how much a gemstone weighs—not its size. Thus, diamond carat refers to the weight of the diamond stone (or its apparent size).

Carat is the standard measurement metric for gemstones and precious stones, particularly diamonds. A metric ‘carat’ is defined as 200 milligrams,  with each milligram sub-divided into 100 ‘points’. This allows precise measurements to the 100th decimal place.

In industry lingo, jewellers and gemmologists may refer to gemstones by the points of their carat weight. For instance a 0.5 carat gemstone may be referred to by a jeweller as a “fifty pointer”.

All other diamond attributes being equal, a diamond’s price will increase with increased carat weight since larger diamonds are harder to come by. Make sure to pay particular attention to the diamond’s cut, since a high carat weight diamond that is poorly cut may look smaller in comparison to a smaller carat weight diamond that is better-cut.

Some diamonds are considered “magic sizes”. Half carat, three-quarter carat and single carat diamonds are such examples. To maximise value of your diamond purchase, consider purchasing a diamond ever-slightly below these magic sizes. The outcome will be visually negligible to the naked eye, but potentially save you big on its cost.

Some settings can also make a diamond appear bigger than they actually are. Halo settings, for example, create a ring of small diamonds around the centrepiece diamond, giving the appearance that the main diamond is larger than it actually is.

Finally, fancy-shaped diamonds may appear larger than their actual carat weight. Shapes like pear diamonds may be worth considering when trying to get the greatest bang-for-your-buck when it comes to carat weight.

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