The four Cs you need to become familiar with are cut, colour, clarity, and carat weight. There is considerably more to know about diamonds but this is a good starting point.

Carat

The concept here is simple – carat refers to the weight of a diamond. The measurement is like centimetres to metres with 100 points (pt) equalling 1 carat (ct). That means a .50 ct diamond is 50 pt, but when it comes to size this will change. For example, a 1 ct round brilliant cut diamond is approximately 6.5 mm in diameter. Given this, you might think that a .50 ct diamond’s diameter is half that size, when in fact its diameter is approximately 5 mm.

Clarity

As the name suggests, clarity relates to the clearness of the stone. All stones are graded upon any impurities (known as inclusions) that are present within the stone, here is an overview of the different grades:

FL: A flawless grade, an FL stone has no inclusions visible by a microscope.

VVS and VS: Stones with a VVS grade have very very small inclusions and stones with a VS grade possess very small levels of inclusions.

SI: The SI grade has some inclusions that can be seen only with a 10x magnification loupe magnifier. To the normal eye, this is a clean stone with clarity.

I: The final grade of stone, I graded stones have inclusions that are visible to the eye. Inclusions can be black, white, or crystalline, which means that some may blend into the stone.

Colour

Nothing says romance like a sparkling white diamond.  White diamonds are colour graded on a scale that ranges from D through to X, with D being colourless and X indicating a yellow tint. White diamonds range from D to J, with each grade indicating different intensities.

A final note about colour: the standards above only refer to white diamonds.  Coloured ‘fancy’ diamonds are rare, so keep this in mind if that is what you are looking for.

Cut

Referring to the quality of the diamond’s cut, this can be the most elusive ‘C’ to understand.  Cut is an important aspect to consider, because it relates to the proportion, finish and symmetry of the external facets that together create the fire and brilliance of the diamond.  If these are not cut to specifics, the diamond will not sparkle and can appear dull and lifeless.