Pierre DeRoche PDR 3002 Mode D'emploi page 18

Clarity
The most widely used scale of clarity is based on an examination
of the precious stone under a 10-power magnification: FL (Flaw-
less, meaning the absence of any internal or external flaws), IF
(Internally flawless), VVS1 (Very very small inclusions), VVS2, VS1
(Very small inclusions), VS2, SI1 (Small inclusions), SI2, SI3, P1
(Piqué), P2 and P3.
Colour
Several grading scales are used, some of which are local, and they
are linked between themselves by correlation tables. Among
the most widely known is the "GIA" (Gemological Institute of
America) scale ranging by decreasing quality from the letter D
(absence of colour) to the letter V (yellow colour). The "Old Terms"
scale is internationally recognised and is the most commonly
used. Stones are classified, by decreasing quality, according to
the following terms: River (Exceptional White), Top Wesselton,
Top Crystal, Crystal, Top Cape, Cape, Light Yellow and Yellow.
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