Learn About Diamonds

The four C’s explained!

The price of a diamond is largely determined by 4 criteria: Carat, Clarity, Colour and Cut. These are the 4 C’s. The 4 C’s are used throughout the world to classify diamonds. All of the C’s are important for a beautiful stone!


This one is the most well known – carat is a measure of the weight of the stone. One carat is equivalent to 200 milligrams. Each carat is divided into 100 “points” so a 0.75-carat diamond is 75 points, or ¾ of a carat. People can presume that half a carat would be half the price of a one-carat diamond, but the larger the stone the rarer it is and the price is reflected!

This refers to the number of natural inclusions inside a diamond. Being a natural mineral, sometimes diamonds can have small fractures or tiny blemishes inside the stone. Think of inclusions as natural identifying characteristics unique to each and every diamond. We have to use a magnifying loupe to see inclusions properly in most cases. Clarity is measured on a scale as follows:

F/IF = Internally flawless, very rare and very valuable
VVS = Very very small inclusions
VS1/2 = Very small inclusions
SI1/SI2 = Small inclusions
I1/I2/I3 = Included enough so that characteristics are visible with the naked eye.
Inclusions within a stone can make a different to how brilliant, or ‘sparkly’ a diamond is. An inclusion in the middle or on the top of a diamond can make a difference to how the light is dispersed inside it, making it less sparkly.

This refers to the degree with which a diamond has NO colour. A diamond is graded on its “colourlessness.” Diamonds are graded on a scale starting with grade D which is completely colourless, to letter Z which is bright yellow. The higher the colour the brighter the diamond! The first three colours ‘D’ ‘E’ ‘F’ are colourless. Colours ‘G’ ‘H’ ‘I’ and ‘J’ are near colourless. As a general rule, Grieve Diamond Jeweller sources majority of our diamonds in colours F – H, as anything lower such as colours ‘K’ ‘L’ and ‘M’ show faint colour and can make the diamond appear dull. It is really pretty simple. The closer to truly colourless ‘D’ you go, the more expensive the diamond because of its brilliance and rarity. Some diamonds are hugely coloured to a point where we call them “fancy coloured” such as pinks, bright yellow, blue, black and champagne (brown) diamonds. These sorts of diamonds can be hugely sought after and are graded on a different scale.

The cut of a diamond isn’t just its shape, cut also refers to the proportions of a diamond. The way diamonds are cut is very scientific. Ideally, a well cut diamond will reflect light internally from one facet to another, then disperse it through the top of the stone. This makes a beautiful brilliant, SPARKLY stone with lots of life in it.

If the diamond isn’t cut well, the light won’t reflect properly resulting in less brilliance.

Cut can also refer to the shape of the diamond:

All of the 4 C’s work together to help us classify and price diamonds. If you have a diamond that is colourless, flawless but not cut properly, it can appear dull and lifeless. Again if you have a diamond that is colourless, perfectly cut but has a big fat inclusion in the middle – not as valuable. Compromising on one of the C’s can help a little if you’re on a limited budget, but we think it is better to have a slightly smaller diamond with good colour, cut and clarity for a really sensible investment.


The pink diamond is the most rare and valuable diamond. 95% of the worlds pink diamonds are found in the Argyle mine. In 1989 a 3.14 ct pink Argyle sold at auction for $1,510,000!

Pink diamonds range in colour from delicate pastel rose to bright raspberry to purple reds. The more intense the colour, the higher the price per carat. Pink diamonds are so exclusive, the best ones are sold by special bids by invitation only.

Champagne diamonds are naturally coloured and range in colour from light straw to rich cognac. When it comes to the 4 C’s, cut, carat and clarity still apply but coloured diamonds are graded slightly differently in colour. Champagne diamonds are graded on a C1-C7 colour scale, 1 being light champagne and 7 being dark champagne.

Yellow diamonds come in a broad range of colours – very pale yellow to a bright rich canary yellow. We have sourced yellow diamonds for customers that have been stunningly beautiful and look absolutely amazing paired with white diamonds to show off their colour.

Diamonds also come in greens and blues. Fancy blue diamonds come in a wide range of shades from sky blue to dark blue with a steel look to them. Green diamonds aren’t very deep in colour and are very rare.

Black diamonds are very fashionable at the moment. They are dark, mysterious and interesting. They are often called “Carbonado” and are made of a slightly different crystalline structure from white diamonds. They absorb light rather than reflect it.

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