The Four C’s You Need to Know About When Buying Diamonds

Diamonds may be a girl’s best friend, but when it comes to buying them, other than knowing they should ‘shine bright’ ( thanks Rihanna!), it’s likely most of us have no idea how to pick a genuine one from the rough. 


As diamonds are forever, choosing the perfect one requires way more than just a sparkle and high price tag.


The arguably most coveted gemstone in the world, diamonds are considered highly valuable as they have incredible strength, rated at 10 on the Mohs scale of hardness (with 1 being softest and 10 most hardest), diamonds are considered the hardest natural mineral on earth.


It’s also the reason they are called diamonds - with the word deriving from the Greek word ‘adamas’ which means invincible or indestructible!’ With such a impenetrable strength and a mesmerising sparkle, it makes sense why diamonds are coveted and adored by everyone around the world.


But before you (or your fiance!) go splashing out on the biggest rock you can find, note that there are a few key considerations that we always look out for when it comes to buying the best diamonds. And it’s as easy as memorising the four c’s!

the four c’s of diamonds:

  • the cut

  • When selecting a diamond, it’s all about the cut. Why? Because no matter how large or smaller diamond you choose, if it’s a poor cut, it will appear dull and not give the same sparkle. True fact!


    The cut and depth affects how much light can enter and reflect back out in order to ‘shine bright’ and sparkle. Of the light that enters a diamond it’s said 20 per cent immediately reflects off the surface but of the 80 per cent, a portion of light escapes to the bottom of the diamond where the observer can’t appreciate it. A well proportioned diamond will be cut to allow the maximum amount of light to enter it.

    To ensure you choose the right cut, look for diamonds that offer a GIA ‘cut grade’ rating of - ‘Excellent, Very Good, Fair, Poor.’ The GIA is an independent organisation that ensures diamonds are correctly and fairly rated based on the quality of their cut (and are the original creators the ‘4 C’s of Diamond Quality’).


  • the clarity

    The simplest way to understand clarity (in the 4 C’s of Diamond Quality) is to think of it like you would human skin - blemish free, clear and glowing. A diamond with high clarity has no tarnishes, specks, roughness or spots, it’s completely transparent and sparkly. A flawless diamond (the one you want!) will have no inclusions, or blemishes visible to the skilled grader even using a x 10 magnification.

    Just as there is a cut grade system, the GIA also offers a ‘GIA Diamond Clarity Scale’, with six categories - flawless, internally flawless, very very slightly included, very slightly included, slightly included and included - to help you find the brightest diamond.

  • the carat

    Not to be confused with the orange vegetable, this kind of ‘carat’ is all about the weight and size of a diamond. The standard metrics for a carat are measured as 200 milligrams for a ‘carat.’

    The technical side of carats can be confusing but essentially each carat is subdivided into 100 points. A jeweler then can determine the diamond carat down to the hundredth decimal place to be incredibly precise - for example, as said explained on the GIA, “a diamond that weighs 0.25 carats can be a ‘twenty five pointer.’”

    Numbers aside, just know this -  the heavier the carat weight, the more rare and expensive the diamond. But of course, it’s not just the carat alone, all 4Cs - clarity, colour, cut and carat are essential in determining the cost and quality of the diamond.
  • the colour

  • The colour is arguably the easiest one to evaluate when choosing a high quality diamond, because it should be completely transparent. A diamond that is considered high value and pure, should be based on the absence of colour, with no hue, much like a drop of water.

    While there is diamonds that come in other colours like yellow and pink, they aren’t considered as high value, so if you’re looking for a true diamond in the rough, look for the most crystal clear.