The 4C’s are an international term used by professionals to to grade colour, clarity, cut and carat weight of a diamond. This is helpful as it allows people to compare the quality and value of a diamond, which is often affected by the rarity of one or more of the 4Cs. Value and rarity are related, in this case, a colorless diamond is more rare and valuable than one with a slight yellow color. The same relationship between rarity and value exists for clarity, cut, and carat weight.
Colour: Diamonds are graded from D – Z; D being colorless and the most desirable through to Z which is yellow, the least desirable. Colorless diamonds are scarce – most diamonds have tints of yellow or brown, so a colorless diamond rates higher on the color grading scale than a diamond that is light yellow.
Clarity: The GIA defines clarity as the absence of inclusions and blemishes. During a diamond’s formation when it’s exposed to extreme heat and pressure, it will often contain unique birthmarks, either internal (inclusions) or external (blemishes). Diamonds are cut to maximize the clarity, the absence of internal flaws. Whilst a diamond, which is internally flawless, is the most desirable they also command the highest prices. A diamond, which has been skillfully cut, can determine where the flaws occur and more often than not are not visible with the naked eye.
Cut: This is an incredibly important element of the 4 ‘C’s as a stone cut to precision is what brings out the most of the diamond’s sparkle. The cut encompasses proportion, symmetry and polish and these are graded from excellent to poor on a GIA diamond certificate.
Carat: This simply means the measurement of weight, not size. There are 100 points in a carat so what’s worth bearing in mind is that as one hits the 1 carat mark, these stones command a premium price within the market. As an example, a half carat diamond might have a diameter 5.1mm, whereas the diameter of a one carat diamond (weighing 100% more) will only increase by a further 25%.