Diamond clarity is determined by the absence of surface blemishes like nicks and scratches and, more frequently, internal features called inclusions. These are often tiny crystals trapped inside a diamond when it was formed. The highest grade of clarity is flawless. That is when a diamond has no blemishes or inclusions visible to an experienced grader at 10x magnification. Such diamonds are so rare that many professional jewellers have never encountered one.
For those diamonds that are less than flawless, clarity grading takes into account not just the number of inclusions but how big they are, what form they take, their colour and position. An inclusion on the underside of a cut diamond would not be as significant as one on the top. That means that each diamond is assessed on its own merits.
11 grades of clarity exist. At the top are flawless and internally flawless. Next are two grades of diamonds considered to be very slightly included (VVS1 and VVS2), two grades of very slightly included (VS1 and VS2), two grades of slightly included (SI1 and SI2) and three grades of included diamonds (I1, I2 and I3). Only those diamonds at the bottom of the scale have inclusions that can be seen by the naked eye. At Harper Tait, we only buy diamonds that range from flawless to SI1.