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Diamond Guide

EC One Owner and Goldsmith Jos Skeates explains the "The Four C's" of diamonds.

A diamond is described by taking into consideration the key elements we call the Four Cs – carat, colour, clarity and cut. Most importantly all diamonds sold at EC One are Conflict Free.


Slightly confusingly, Diamond colour actually measures its lack of colour!

Diamond colour is graded from D (colourless) to Z (tinted) using the international colour grading scale as reference. The closer a diamond is to colourless, the rarer and more valuable it is. At EC One our diamonds are G colour and above.

'Fancy coloured diamonds' have a strong, even colour such as yellow, pink or blue. They are very rare, consequently making them very expensive. Natural brown diamonds, also called Cognac or Champagne diamonds, are growing in popularity and are a gorgeous alternative to the classic white diamond.


Natural diamonds are created when carbon is exposed to great heat and pressure deep in the earth. During this process a variety of internal characteristics called ‘inclusions’ and external characteristics called ‘blemishes’ occur.

Grading a diamond's clarity involves determining the number, size, type and position of these 'inclusions' and how they affect the look and durability of the stone. Every diamond is unique and can be recognised by its own fingerprint of these little marks.

Remember that no diamond is perfectly pure. But the closer it comes to purity, the better its clarity is.

Clarity grading ranges from internally flawless stones (FI/IF) to those that have tiny inclusions which can just be seen by the naked eye. EC One uses diamonds of S1 clarity and above.

Flawless (FL) No inclusions and no blemishes visible under magnification.
Internally Flawless (IF) No inclusions visibleunder magnification. 
Very, Very Slightly Included(VVS1 and VVS2) Inclusions so slight they are difficult for a skilled grader to see under magnification.
Very Slightly Included (VS1 and VS2) Inclusions are observed with effort under magnification.
Slightly Included (SI1 and SI2) Inclusions are noticeable under magnification.
Included (I1I2, and I3) Inclusions are obvious under magnification which may affect transparency and brilliance and even durability.


The brilliance of a diamond is determined by the precision with which it is cut. Perfect proportions allow light to reflect internally and disperse through the top of the diamond, giving it that unmistakable sparkle.The look of an excellently cut diamond is made up of:

Brightness: The white light reflected from a diamond.

Fire: The breaking up of white light into all the colours of the rainbow.

Scintillation: The amount of sparkle a diamond produces, and the pattern of light and dark areas caused by reflections within the diamond.


The Carat weight of a diamond is how much it weighs and so is a very good indication of its size.

History suggests a ‘carat’ was equal to the weight of a single carob bean, used in the past when gemstones were traded. A metric “carat” is defined as 200 milligrams. Today diamonds are described in carats and points. A one carat (1ct) diamond equates to 100 points, so a 1/2 carat (0.50ct) is 50 points.

The larger the carat weight of a diamond, the rarer and more valuable it becomes – though clarity and colour will also determine its value.

Not one of the 4 C's but great to understand nonetheless...


Often confused with Cut, this is the Shape the diamond has been cut into.


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