While we idealize diamonds for their seeming perfection, almost all diamonds are imperfect in some regard. Most diamonds contain flaws in the form of inclusions (subsurface flaws) or blemishes (surface flaws). Clarity is a scale that illustrates how visible these imperfections are to the naked eye because it affects the passage of light through the diamonds facets, or brilliance.
Diamond Clarity Scale
Diamonds are graded for clarity using the 11 point diamond clarity scale created by the GIA, although not all diamonds have been graded by GIA. The GIA considers the number, size, color, reflectivity, and position of every flaw visible under 10x magnification.
The clarity scale extends from FL (Flawless) to I3 (Included:3).
Flawless (FL) : No inclusions or blemishes are visible to a skilled grader using 10x magnification. The rarest clarity level among diamonds.
Internally Flawless (IF): No inclusions, only blemishes are visible to a skilled grader using 10x magnification. Without magnification, IF stones appear flawless.
Very, Very Slightly Included (VVS1 – VVS2): Inclusions are difficult for a skilled grader to see under 10x magnification. VVS1 versus VVS2 clarity is determined by where the flaw is visible, either in the pavilion or the crown of the diamond.
Very Slightly Included (VS1 – VS2): Inclusions are clearly visible under 10x magnification but can be characterized as minor. Considered all but invisible to the naked, untrained eye, often requiring magnification.
Slightly Included (SI1 – SI2): Inclusions are noticeable to a skilled grader using 10x magnification. The difference between SI1 and SI2 is how visible the flaws are to the naked eye, without training.
Included (I1 – I3): Inclusions are obvious under 10x magnification and may affect transparency and brilliance. Visibly included – the more severely included diamonds (I3) may have lose durability and be susceptible to fracture.