A Guide To Diamonds

Diamonds: A Guide To The 4 Cs


Choosing a diamond for an engagement ring or bespoke piece of jewellery can be a little daunting and there is a lot of confusing information out there. This quick guide will give you a simple understanding of how a diamond is valued/graded so you can choose that all important stone with confidence.


Diamonds are the hardest naturally occurring material known to man, the name originates from the Greek word Adamus meaning unconquerable. Created deep within the earth over 1 to 3 billion years ago each diamond is unique and there are many factors to consider when valuing each one. To determine a stones quality jewellers use what is known as the 4Cs, an internationally recognised grading system that accurately measures Cut, Carat, Colour and Clarity. 


Here is our low down on the 4Cs.




Of all the 4 Cs the Cut can have the greatest influence on a stones quality. The cut refers to the shape of the diamond but is graded on how well proportioned the stone is. It is the job of a skilled stone cutter called a lapidary to take a rough mined diamond and precisely shape and polish it into a beautiful gemstone.

How symmetrical the stone is cut determines how well its facets interact with the light. As light travels into the stone it is bounced from facet to facet and reflected back out of the stone which creates the flashes and sparkles diamonds are famous for. 

The most popular shape is the round brilliant cut which has 58 facets and is designed for maximum sparkle, other shapes such as ascher or emerald are cut to play with the light differently and allow you to see further into the stone.




A diamonds weight is measured in Carats, one carat is the equivalent of 0.2 grams, or a 1 carat round stone would be roughly 6.4mm. A carat can be sub divided into a hundred points, so even very small stones can be weighed. When viewing diamonds a jeweller may describe a stone below 1 carat by its points alone so a 0.30 carat diamond would be called a thirty pointer.

Larger stones are rarer and it can be a natural instinct to go for the biggest stone however it is a combination of all of the 4 Cs that determines a diamonds value.



Most diamonds are graded on a colour scale from D - Z, D being the most valuable because it is completely absent of colour which enhances the crisp pure characteristics of the stone. The amount of colour present increases very gradually through the scale and the subtleties in colour between two grades can be impossible see to the untrained eye.

Naturally occurring coloured diamonds known as Fancies are found in pink, green, blue, brown, champagne and yellow but are very rare. Rather than being graded on the absence of colour they are graded on the intensity of their colour. I particularly like brown and champagne diamonds which compliment gold or platinum beautifully.




A Diamond is formed deep within the earth when Carbon is exposed to extreme heat and preassure. This natural process means characteristics called inclusions (internal flaws) or blemishes (external marks) are present within the stone.

A diamonds clarity in measured when viewed under 10 x magnification, how many inclusions can be seen, their size and position all affect its clarity rating. All diamonds contain flaws but a diamond whose inclusions are to small to see under magnification is considered flawless and is extremely rare.


Gaining a little understanding of the 4 Cs can be very helpful but it’s important not to get too hung up on any one characteristic, finding the best balance between all four that your budget will allow will result in a great stone.

You can find more information on commissioning a hand crafted piece from us on our bespoke page.