A diamond’s clarity is determined by the number, nature, position, size and color of internal characteristics called “inclusions” and surface features called “blemishes”. The clarity grade in detail expresses the degree to which the stone contains surface blemishes and or inclusions. Generally, and particularly with diamonds, the lack of these features is the most desirable condition. Inclusions can be all sorts of things: breaks, other crystals, clouds, growth lines, bruises, and pinpoints. Blemishes include: extra facets, pits, cavities, chips, nicks, abrasions, and scratches. Grading should always be done under 10 power magnification and proper lighting.
FL – Flawless
These stones have no imperfections inside or on the outside of the stone under the magnification of a loupe of 10 power. Extremely rare and beautiful diamond.
IF – Internally Flawless
These stones have no inclusions under a loupe with a 10 power magnification. An excellent quality diamond. Very rare and beautiful diamond.
VVS1, VVS2 – Very Very Slightly Imperfect
These stones have very small inclusions which are very difficult to see under a loupe with a 10 power magnification.
VS1, VS2 – Very Slightly Imperfect
These stones have small inclusions which are slightly difficult to see under a loupe with a 10 power magnification. Less expensive than the VVS1 or VVS2 grades.
SI1, SI2 – Slight Imperfect
These stones have inclusions which are fairly easy to see under a loupe with a 10 power magnification, or visible to the naked eye. A good diamond value.
I1, I2, I3 – Imperfect
These stones have inclusions which range from eye visible to very easily seen to the naked eye. These are mainly commercial quality diamonds.