The Four C's - Colour, Clarity, Cut and Carat

When it comes to buying diamonds, it is helpful to learn a bit of the lingo, such as The Four C's - Diamond Colour, Clarity, Cut and Carat. The diamond specification of your jewellery will give details about the Four C's.

Diamond Colour

Diamond Colour is essentially what it says on the tin. It is the specific 'colour' of the diamond and is measured on a sliding scale from colourless (D) to yellow-y/brown (Z).

  • D - F = colourless. The rarest Colour grade and in turn the most valuable.

  • G - J = near colourless. The most common Colour grade of diamond used in retail jewellery.

  • K - M = faint.

  • N - R = very light.

  • S - Z = light. Often avoided when looking for a bright, clear stone. This is also the least valuable Colour grade of diamond.

Additionally, Florescence is a notable quality when it comes to diamond Colour and shows up blue when under UV light. The more florescence in a diamond, the cloudier it appears when in natural light too.

Diamond Clarity

The Clarity of a diamond is determined by the number of characteristics found within it e.g. black flecks, cloudy sections. It is measured from Internally Flawless (IF) to Included (I3).

  • IF = Internally Flawless. This is the most valuable Clarity grade as it is the rarest and also has no inclusions.

  • VVS1 - VSS2 = Very Very Slightly. These diamonds show only a few characteristics which aren't really visible by eye.

  • VS1 - VS2 = Very Slightly Included. Slightly more inclusions would be seen in these diamonds, but again they are not too visible by eye.

  • SI1 - SI2 = Slightly Included. This is the most common Clarity grade of diamond used in fashion jewellery. It has some characteristics that can be seen but only through a jeweller’s loupe.

  • I1 - I3 = Included. These diamonds show visible characteristics. A diamond with a lot of visible inclusions will be less valuable.

Diamond Cut

The Cut of a diamond is the man-made shape of a diamond which is determined by the angle, number, size and shape of the diamonds facets (or sides)The most common Diamond Cut is a Round Brilliant Cut. We have put together a more in-depth article on the Different Diamond Cuts, here.

Diamond Carat

Diamond Carat is the overall weight of the diamond and is normally abbreviated to 'cts' or sometimes 'kts'. It's pretty tricky to know what 1 carat looks like in contrast to 0.33 carats. So, to put it in a more relational way, here is a rough example of carats in comparison to the rough diameter across a diamond (for a Round Brilliant Cut):

  • 0.1 cts = 3.0 mm

  • 0.25 cts = 4.1 mm

  • 0.50 cts - 5.2 mm

  • 1 cts = 6.5 mm

There is also more diamond information on the GIA website.

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