Because diamonds formed deep within the earth, under extreme heat and pressure, they often contain unique birthmarks, either internal (inclusions) or external (blemishes).
Diamond clarity refers to the absence of these inclusions and blemishes. Diamonds without these birthmarks are rare, and rarity affects a diamond’s value. Using the GIA International Diamond Grading System™, diamonds are assigned a clarity grade that ranges from flawless (FL) to diamonds with obvious inclusions (I3).
Every diamond is unique. None is absolutely perfect under 10x magnification (using a jewelers loupe), though some come close. Known as Flawless diamonds, these are exceptionally rare. Most jewelers have never even seen one.
The GIA Clarity Scale contains 11 grades, with most diamonds falling into the VS (very slightly included) or SI (slightly included) categories. In determining a clarity grade, the GIA system considers the size, nature, position, color or relief, and quantity of clarity characteristics visible under 10x magnification.
- Flawless (FL) – No inclusions or blemishes are visible to a skilled grader using 10x magnification
- Internally Flawless (IF) – No inclusions and only blemishes are visible to a skilled grader using 10x magnification
- Very, Very Slightly Included (VVS1 and VVS2) – Inclusions are difficult for a skilled grader to see under 10x magnification
- Very Slightly Included (VS1 and VS2) – Inclusions are clearly visible under 10x magnification but can be characterized as minor
- Slightly Included (SI1 and SI2) – Inclusions are noticeable to a skilled grader using 10x magnification
- Included (I1, I2, and I3) – Inclusions are obvious under 10x magnification and may affect transparency and brilliance