An experienced professional uses a 10x power magnification in standardized light to examine the clarity grade.
FL – Flawless – Loupe clean: no external or internal features.
IF – Internally Flawless – no inclusions and only minor external features, with the exception of small external growth lines.
VVS1, VVS2 – Very Very Slight Inclusions: very very small inclusions, which are very difficult to see.
VS1, VS2 – Very Slight Inclusions: smaller inclusions ranging from those which are difficult to see, to those which are somewhat easier to see.
SI1, SI2 – Slight Inclusions: inclusions, which are easy (SI1) or very easy (SI2) to see. The inclusions are often in a central position and can be immediately recognized and, in some cases, are also visible to the naked eye.
I1, I2, I3 – Pique: distinct inclusions which in most cases are easily visible to the naked eye through the crown; in the case of I3, stone durability can be endangered.
SI3 commercial clarity grade is not accepted by GIA.
P1, P2, P3 commercial clarity grades, some gemological laboratories accept these grades, especially laboratories recognized by CIBJO in Europe.