Diamonds and the 4C’s – How a Diamond Gets its Value

If you don’t believe in miracles, then explain to me how a piece of coal becomes a diamond? Let’s talk about these sparkling miracles and how we grade and value them, by using the 4C’s.


The 4Cs

GIA (Gemmological Institute of America) created the globally accepted standard for describing diamonds: Colour, Clarity, Cut and Carat Weight. So today, the 4Cs of Diamond Quality is the universal system for assessing the quality of any diamond. The creation of the Diamond 4Cs ensure diamond customers like yourself, now know exactly what you are about to purchase.

So that’s all well and good but what do those words actually mean!?



The colour of a Diamond is graded from D-to-Z, this system measures the degree of colourlessness of a Diamond. The colour evaluation of most diamonds is based on the absence of colour. The less colour in a Diamond, the higher the value, a structurally perfect Diamonds has no colour whatsoever.

The scale begins with the letter D, representing completely colourless, and continues, with increasing colour, through to the letter Z.



Diamonds are created deep in the earth’s core, when carbon is exposed to huge amounts of pressure and heat (ahem, miracles!) This process can result in a variety of internal characteristics called ‘inclusions’ and external characteristics called ‘blemishes.’ While every Diamond will have some form of inclusion or blemish, the closer it is to Flawless, the higher the value.

Many inclusions and blemishes are too small to be seen by the naked eye but the further down the clarity scale, the more visible they are. I like to think of inclusions as a Diamonds personality! Each Diamond is unique.



Diamonds are known for their ability to transmit light and sparkle immensely. We often think of a diamond’s cut as shape (princess, pear or round), but a diamond’s cut grade is actually about how well a diamond’s facets interact with light.

Diamond cutting is an art and takes precision to fashion a stone, so its proportions, symmetry, and polish deliver the magnificent return of light only possible in a diamond. The quality of cut is crucial to the diamond’s final beauty and overall value.



Diamond carat weight is the measurement of how much a diamond weighs. A metric “carat” is defined as 200 milligrams.


The modern carat system started with the carob seed. Early gem traders used the small, uniform seeds as counterweights in their balance scales.


All else being equal, diamond price increases with carat weight, because larger diamonds are rarer and more desirable. But two diamonds of equal carat weight can have very different values (and prices) depending on three other factors within the 4Cs: Clarity, Colour, and Cut. It’s important to remember that a diamond’s value is determined using all of the 4Cs, not just carat weight. Unlike coloured gemstones, a diamond will suit everyone – if you would like us to source you a Diamond for your perfect engagement ring then please get in touch by clicking the link below.

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