Of the 4 Cs, diamond clarity is the least complicated characteristic to understand. A diamond's clarity refers to the amount of flaws in the stone. Almost all diamonds naturally contain imperfections, either on the surface or inside the stone, and the grade of a diamond's clarity reflects the scale of these flaws. Imperfections inside the stone, such as scratches and coloured marks, are called inclusions in the diamond industry. Air bubbles, cracks or other flaws on the surface itself are called blemishes.
A diamond receives a clarity grade after its imperfections are examined at 10x magnification. This means that many of a diamond's inclusions and blemishes are completely undetectable by the naked eye, so consumers should not be overly concerned about buying such diamonds. A clarity grade reflects the different characteristics of a stone's flaws, including their size, colour, and position. Many of these so-called flaws are completely natural and are not an indication of defectiveness.
Many consumers are under the impression that they should only be buying diamonds of the highest clarity grade. The flaw in this reasoning is that Flawless (FL) and Internally Flawless (IF) diamonds are extremely rare and can cost a small fortune. Many stones possess inclusions that are difficult to find even for experts examining the diamond with a magnifying lens, so for most buyers it's a much smarter decision to save money by buying an "imperfect" diamond that will still look flawless to observers.
Almost as rare as FL diamonds, IF diamonds have no inclusions and are desired for their rarity
These diamonds contain inclusions but they are difficult to see, even upon a close inspection. For many consumers, these diamonds represent extremely high quality stones at a more affordable price than FL/IF diamonds
Slightly more pronounced inclusions than the higher clarities, but the flaws in the stone are unable to be seen by the naked eye. It is only under 10x magnification that the inclusions will be detectable.
More affordable than VS grade diamonds, the small inclusions are more easily noticed upon magnification. For those on a tighter budget, SI1 diamonds represent the convergence of affordability and quality.
With more inclusions than SI1, this grade of clarity is cheaper but may contain inclusions that are visible even without magnification.
These stones will have inclusions that can definitely be seen under magnification, and may possess imperfections that are immediately apparent to the naked eye.