A diamond's clarity refers to imperfections found on the surface or internally. Internal flaws are called inclusions, whilst external imperfections are referred to as blemishes. The majority of diamonds, both mined and lab-grown, feature inclusions and blemishes on a microscopic scale, which is why even diamonds with the highest clarity grade feature slight inclusions. At the Diamond Library, we reject 60% of all gem-grade diamonds, which is a level above the average. The minor inclusions featured in our lab-grown diamonds are entirely invisible to the naked eye.