Cut
Most people in the jewellery trade think that the ‘cut’ is the most important of the 4’cs when it comes to determining how much a diamond sparkles.
We use the word to not only describe the shape of the diamond, but also how well the facets are arranged, how symmetrical they are and how smooth their surfaces are.
There are two main types of cut, step cuts and brilliant cuts and a wide range of diamond shapes.

Colour
Diamonds are graded on a scale from D to Z and this scale measures how ‘white’ or ‘colourless’ a diamond is. The scale starts at D in case diamonds that are whiter are ever found and diamonds at the higher end of the scale are worth more.
Grades D-F are described as 'colourless' and fetch a premium, especially D.
The colour scale we use today was
How important is the colour of a diamond?
We place quite a lot of importance on the colour of a stone because it covers the whole stone. With clarity, unless your looking under a microscope, you wont be able to see the inclusions, but with the colour, it's the entire stone and you can see it at glance. (or across a room if the stone's big enough)
Clarity
The clarity of a diamond is graded on a scale from IF to PK and refers to the amount and type of natural inclusions a diamond has.
Diamonds with fewer or no natural inclusions are rarer and more valuable however its a matter of taste and diamonds with prominent inclusions known as ‘salt & pepper’ diamonds are extremely popular.


Carat
The carat refers to the size of a diamond and is derived from the weight of a carob seed. 1 ct is 1/5th of a gram and is made up of 100 points.
A 1ct round brilliant with good proportions should have a diameter of 6.5mm
The other C’s
Certification
A diamond that comes with a certificate has been inspected by experts in a lab and graded to a set of criteria
The GIA is the industry leader for certified diamonds and they have lab’s all over the world dedicated to diamond and gemstone testing and grading