The term "eye-clean" is used to describe a diamond that is free of visible inclusions or blemishes to the naked eye. Inclusions are internal characteristics or flaws in a diamond, while blemishes are external flaws on the surface of the diamond. Eye-clean diamonds are considered to be of higher quality and are typically more valuable than diamonds that are not eye-clean, as inclusions and blemishes can affect a diamond's transparency, sparkle, and overall appearance. When evaluating the eye-cleanliness of a diamond, the size, number, and location of the inclusions and blemishes are taken into consideration. If inclusions or blemishes are not visible from a distance of 6 to 12 inches, the diamond is typically considered eye-clean. However, this can vary depending on the individual's visual acuity and the size and quality of the diamond.