The 4Cs Diamond Guidance

Diamonds Anatomy

Even though each and every diamond is unique, they all share certain characteristics. A diamond's basic structure or 'anatomy' has a direct effect on its proportions, brilliance, dispersion and scintillation.

When it comes to inspecting any diamond, the three most important components are diameter, table and depth. You'll also be able to divide any diamond into two key sections - the Crown and the Pavilion.

It helps to have a basic understanding of each component and section, as this means you'll be able to find your perfect diamond. However, this knowledge should not supersede the importance of or be confused with cut grade.

The cut of a diamond not only refers to its shape but also how well the stone reflects light. Simply put, it's responsible for the quality and degree of a diamond's sparkle. The better the cut, the more scintillation the diamond will have.

Precise artistry and workmanship are required to cut a diamond so that its proportions, symmetry and polish return the maximum amount of light possible.

For many people, this is the most important of the 4Cs because it determines the beauty of a diamond. Whereas two diamonds may have the same clarity, colour and carat weight, cut is what determines whether or not one is superior to the other.

The GIA Grading Scale for Diamond Cuts

The Gemmological Institute of America (GIA) has a cut grade that determines how well a diamond sparkles. It evaluates:

How the diamond appears when viewed face-up based on the attributes of brightness, fire and scintillation

How well the diamond was designed to ensure durability and optimal weight.

The quality of the workmanship or craftsmanship that went into aligning and polishing the diamond’s facets

Diamond cut grades are assigned into the following categories:

Excellent (EX)

High brilliance, scintillation, and an even pattern of light and dark areas. Seeing as almost all of the incoming light is reflected through the table, the diamond radiates with magnificent sparkle.

Very Good (VG)

Also featuring high brilliance and scintillation but slightly darker in the centre or around the edges. To the naked eye, Very Good diamonds provide similar sparkle to those of Excellent grade.

Good (G)

Stones with this grade will be a bit darker or lacking in scintillation. Much of the light still reflects through the table to the viewer’s eye, meaning these diamonds provide superb value.

Fair (F)

Very little brilliance or scintillation, as light easily escapes through the bottom and sides of the diamond. They may still be a satisfactory choice for smaller carats or side stones.

Poor (P)

Poor proportions and show very little brilliance or scintillation. Entering light escapes from the sides and bottom of the diamond.

How is Diamond Cut Measured?

The GIA cut grade combines three different types of reflections:


The brightness created by the combination of white light reflections inside and on the surface of the stone. Well-cut diamonds are brighter than poorly fashioned ones, even if they’re of equivalent size, colour and clarity.


The spread of white light which appears as flashes of all the colours of the spectrum. When you tilt a diamond under light, you should be able to see red, blue, yellow or orange flashes.


This takes both sparkle and pattern into consideration. Sparkle refers to the spots of light that flash when the diamond, you or the light source moves, while pattern is the relative size, arrangement and contrast of the diamond's bright and dark areas.

By studying how successfully a diamond interacts with light to create these desirable visual effects, a cutter can evaluate what the best cut for any given stone is.

Tips for Buying Diamonds with Cut in Mind

It is near impossible to see the difference between an Excellent and a Very Good cut diamond with the naked eye because the direction of light is the same in both cut gradings.

If you're on a budget, a Good cut diamond offers a superb-value alternative without major compromises or quality defects. However, be careful you are not on the "Deep" side because this means the diamond will look smaller than the actual carat weight.

Don't forget that diamond cut, and diamond shape, are not the same thing. Diamond cut assesses the light performance of a diamond and is based on its proportions, symmetry, and polish. Diamond shape refers to the outline of a diamond, the most popular of which is the round brilliant.

Don’t underestimate the importance of diamond cuts. A well cut 0.90ct diamond could have the same width and give out more brilliance than a poorly cut 1.00ct diamond.

Even if you know what a diamond’s cut grade is, this shouldn’t be a substitute for seeing the diamond itself in person. After all, two diamonds with the same grade may look and perform very differently, especially under varying light conditions.

Despite its terminology, diamond colour actually means the lack of colour in diamonds. In nature, most white diamonds have a slight tint of yellow.

Therefore, the diamond trade has a colour grading scale based on the amount of yellow present in a diamond, which is visible when viewed face down through the pavilion using daylight equivalent light. The higher the colour grade of the diamond, the more colourless that diamond is.

Completely colourless diamonds are rare, which is why they come with a higher pricing premium. But deciding whether or not you want to spend more on diamond colour grade will depend on the size and shape of the diamond that you are considering too.

The GIA Grading Scale for Diamond Colour

Colour D

The highest colour grade attributed to a diamond, meaning that the stone is completely colourless (white). They are extremely rare and command the highest prices.

Colour E

Even though E stones are slightly cheaper than D stones, the difference is often only visible to an expert gemmologist using master stones as a comparison.

Colour F

Again the difference between E and F is only visible to an expert. F grade stones are the lowest and least expensive of the premium colours.

Colour G

Nearly colourless, especially once set in jewellery. G graded stones represent excellent value for money.

Colour H

Generally considered the watershed between colourless diamonds and slightly tinted diamonds. They appear totally white or colourless when not compared with higher graded stones.

Colour I

Although slightly tinted, I graded stones may appear colourless once set in jewellery. A great option for maximising your budget.

Colour J

Very slightly tinted diamonds that are suitable for setting in yellow gold jewellery, as the colour will become less visible.

Colour K

Once again, the tint in K coloured diamonds will reduce when set in yellow gold jewellery.

Colour L

Faint yellow hues are more obvious in L graded diamonds. For this reason, several jewellers won't stock grades below L.

How Colour can Change Based on Size, Shape and Setting

Colour is more visible in larger diamonds. So if you're buying a diamond under 1 carat, you might only need a stone graded I, J or K. Then again, diamonds over 1 carat should be H colour-graded or higher otherwise a tint could be visible.

You will also find that certain fancy-shaped diamonds hide colour better than others and can cost up to 25% less than the most desirable round-cut diamond.

If your diamond is going to be set in a precious metal like 18 carat yellow or rose gold, you should consider a diamond with a slightly lower colour grade. The warmer colour tones of these metals will highlight the bright white appearance of the diamond rather than any perceivable tint.

You may even decide that colour is a good thing. After all, diamonds occur in the natural rainbow spectrum of colours - red, orange, yellow, green, blue, pink, purple, and more. Around 1 in every 10,000 diamonds possess natural colour, and the more intense the colour, the more valuable the diamond.

Fancy-coloured diamonds are graded on a separate colour scale and can be even more valuable than white diamonds.

Tips for Buying Diamonds with Colour in Mind

With premium colourless diamonds, the differences between D and G graded stones are barely visible but can provide 20-40% better value. D graded stones tend to be bought by investors or diamond aficionados.

Seeing as H graded diamonds sit on the fence between premium colourless and tinted diamonds, they offer superb value. Unless compared side-by-side with a wider diamond, you will struggle to see any visible yellow or brown tint either.

With I and J graded stones, you should only be able to detect slight yellow or brown tints when viewed from multiple angles. When viewed face down from the top, they appear white.

K and L graded stones are still acceptable on a GIA certificate when it comes to tint. However, it is recommended to set these diamonds in yellow or rose gold jewellery to make the diamond appear less tinted.

Diamond clarity refers to the presence of certain characteristics on (blemishes) and within (inclusions) the stone. As you would expect, diamonds with no or few blemishes and inclusions command a higher price because they are rarer - most diamonds are not flawless in appearance.

Diamond blemishes include scratches, pits and chips, which often occur during the cutting process. Inclusions on the other hand are naturally occurring - when diamonds are formed deep in the earth under extreme pressure and heat, imperfections in the crystal structure can lead to natural birthmarks and irregularities.

Evaluating diamond clarity involves a process that will determine the number, size, relief, nature, and position of its blemishes and inclusions, along with how these affect the overall appearance of the stone.

The GIA Grading Scale for Diamond Clarity

All diamonds are systematically graded and plotted under 10X magnification. The diamond trade uses the Gemological Institute of America (GIA) grading system, which tags diamonds in the following categories:


Flawless diamonds have no inclusions or blemishes when viewed under 10X magnification by a skilled grader.

Internally Flawless (IF)

An IF diamond has no inclusions and only blemishes when viewed under 10X magnification.

Very, Very Slightly Included (VVS1 and VVS2)

VVS diamonds contain minute inclusions that are difficult for a skilled grader to see under 10X magnification. Inclusions in a VVS1 diamond are extremely difficult to see face-up, while inclusions in a VVS2 diamond are very difficult to see.

Very Slightly Included (VS1 and VS2)

Very little brilliance or scintillation, as light easily escapes through the bottom and sides of the diamond. They may still be a satisfactory choice for smaller carats or side stones.

Included (I1, I2, and I3)

Diamonds in the 'I' clarity range contain inclusions that are obvious under 10X magnification.

There are many misconceptions about the clarity of diamonds, such as the belief you need to buy a higher grade to avoid seeing imperfections. Many people also think that the higher the clarity grade, the more sparkle your diamond will have.

The truth is that 99% of diamonds are imperfect, and experts will value a stone's blemishes and inclusions as marks of character. Therefore, any diamond you buy will be unique and one-of-a-kind.

There are several different types of imperfections found in diamonds, but feathers and crystals are the most common forms of inclusions. Other flaws include air bubbles, cracks, non-diamond minerals, clouds, knots, pinpoints and lasers lines.

Five diamond clarity factors to be aware of include:

Size - The larger a characteristic, the lower the clarity grade.

Number - Fewer characteristics means a higher clarity grade.

Position - The position of any given characteristics could turn it into a reflector.

Nature - The type of inclusion and its impact on durability.

Colour and relief - This is a measure of how easily a characteristic is seen.

Tips for Buying Diamonds with Clarity in Mind

Diamond shape and size have a direct impact on clarity. Although clarity is less important than a diamond’s cut or colour, it can be an issue if you are buying a diamond over 1 carat or considering certain fancy-shaped diamonds (such as an emerald or Asscher cut where flaws are more visible).

Consider starting your search with Slightly Included (SI) and Very Slightly Included (VS) grades, as inclusions will not be readily noticeable without magnification. Clarity is one of the 4Cs that can help you maximise your budget.

If imperfections are a deal breaker for you, look for the term 'eye clean'. This refers to a diamond or an inclusion that is not visible to the unaided eye when the diamond is held face-up (viewed through the table) at a normal viewing distance of 10 to 12 inches.

Despite the fact that SI1 and SI2 are not eye clean, their imperfections may be light in colour or scattered. As a result, SI1 graded diamonds may appear to be eye clean in up to 20% of cases.

Because magnification is required to view imperfections in diamonds with a VS1 grading or higher, this is somewhat of a subjective quality choice that goes beyond what can be seen with the naked eye. Larger diamonds at these grades are incredibly rare and as such command a premium price. They're often bought by diamond connoisseurs or investors.

A diamond carat is the internationally recognised unit of measurement used to specify the stone's weight.

One carat is equal to 200 milligrams, which means a 5-carat stone would weigh 1 gram. However, the diamond trade also uses fractions of a carat which are referred to as 'points'. So, a 1-carat diamond would weigh 100 points.

Many people believe carat refers to a diamond's size, not its weight. Another misconception is that a larger carat weight is always better than a smaller carat weight. But a high carat weight diamond with a poor cut may look smaller and have less sparkle than a diamond with a lower carat weight and a very good cut.

The History of Diamond Carats

The term carat comes from the Ancient Greek and Arabic method of weighing precious metal and stones against the beans of the carob tree. Each of the tree's long green beans contained seeds, which were considered to be even in weight. One seed equalled one carob, which is likely where the term carat originates.

It wasn’t until 1907, at the Fourth General Conference on Weights and Measures, when it was agreed upon that one diamond carat would be equal to 200 mg, or .2 grams, of a diamond.

In 1913 the United States officially accepted the carat as the gemstone measurement, closely followed by the United Kingdom and Europe a year later. By the 1930s, the majority of the diamond and gemstone industry had agreed to the standardised measurement.

The Impact Carat Has on a Diamond's Price

Rough diamonds come in all shapes and sizes, as well as different colours and purities. The larger, whiter and cleaner the diamond, the more rare it is.

Therefore, the cost per carat of a large diamond with the same colour, clarity and cut will cost more than a smaller diamond. But that doesn't mean to say the price per carat of diamonds is steady, as they can increase exponentially. For example, a 1 carat diamond would be valued higher than two 0.50 carat diamonds of the same quality.

Even so, some diamond cutters will sacrifice brilliance to maximise profit, as more carat weight generally means more money. This means that diamonds cut poorly to maximise size could quite easily be dull and lifeless - weight alone does not equal beauty.

Other diamond cutters will intentionally sacrifice weight so they can focus on a better cut and thus obtain brilliant diamonds that sparkle and shimmer. If they are of a slighter lower carat weight, they could be available at a more affordable price.

Tips for Buying Diamonds with Carat Weight in Mind

When comparing similar diamonds, focus on its measurements. You'll find certain diamonds with similar weights can vary significantly in measurements. It's advisable to choose the one with wider measurements because you will benefit from a larger diamond surface area for the same value.

You should also consider diamonds of varying shapes, which could be the same carat weight but priced differently. For example, round diamonds are typically more expensive than other shapes because they produce the most waste in their cutting process.

Select a carat weight that is slightly below the whole and half-carat marks. For example, rather than purchasing a 2.00 carat diamond, think about a 1.90 carat weight instead. You will save yourself a considerable amount of money, but the difference will be unnoticeable.

Keep the size of your fingers in mind when buying a diamond ring. If you've got slim fingers and want a fairly basic metal band, you won't need to buy a large carat weight. But if you've got larger fingers and want something more extravagant, you'll probably need a heavier carat weight.

So what carat weight is right for you? Well, a lot depends on personal preference and budget. Just remember that with diamond rings, the most visible aspect of the stone will be its surface area at the top.

You should also consider the diamond’s cut and diameter, as this will have an impact on its aesthetic. Carat has the biggest effect on a diamond’s price, but more expensive doesn’t always mean better stone.

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