A diamond’s clarity is measured by the existence or absence of visible flaws. Tiny surface blemishes or internal inclusions, even those seen only under magnification, can alter the brilliance of the diamond and thus affect its value. Clarity levels are in order of importance:
- Flawless (FL, IF)
- Very, very slight (VVS1, VVS2)
- Very slight (VS1, VS2)
- Slightly included (SI1, SI2)
- Included (I1, I2, and I3)
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FL (Flawless) - No external marks or internal inclusions visible to a trained eye under 10x magnification.
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IF (Internally Flawless) - Only minor surface blemishes but no internal inclusions visible to a trained eye under 10x magnification.
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VVS1, VVS2 (Very, Very Slightly Included) - Few, very small inclusions and/or finish faults, difficult for a trained eye to see under 10x magnification. Typical flaws include tiny pinpoints, faint clouds, tiny feathers, or internal graining.
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VS1, VS2 (Very Slightly Included) - Very small inclusions and/or finish faults, somewhat difficult for a trained eye to see under 10x magnification. Typical flaws include crystals, feathers, distinct clouds and groupings of pinpoints.
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SI1, SI2 (Slightly Included) - Small inclusions and/or surface blemishes easily seen under 10x magnification, but not visible to the naked eye (with SI2, slight flaws may be eye-visible to the trained eye, but virtually impossible to see to the untrained eye). Typical flaws include crystals, clouds and feathers.
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I1 (Imperfect 1) - Inclusions and/or finish faults visible under 10x magnification, but hard to see with the naked eye. Little effect on the brilliancy of a stone, depending on cut quality.
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I2 (Imperfect 2) - More inclusions and surface blemishes visible without 10x magnification. Possible slight diminished brilliancy within stone, depending on cut quality.
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I3 (Imperfect 3) - Many and/or large inclusions and surface faults clearly visible without 10x magnification. Slight diminished brilliancy within stone, depending on cut quality.