FL-Flawless - These stones have no imperfections inside or on the outside of the stone under the magnification of a loupe of 10X magnification.

IF-Internally Flawless - This grade is awarded to stones with no internal flaws and only minor external blemishes. Nicks pits or girdle roughness, not on the
table, which could be removed in re-polishing.

VVS1 , VVS2 - Very Very Slightly Imperfect - These stones have very, very small inclusions, which are extremely difficult to see under a loupe of 10X
magnification.

VS1, VS2 - Very Slightly Imperfect - These stones have very small inclusions, which are slightly difficult to see under a loupe of 10X magnification.

SI1,SI2-Slightly Imperfect - These stones have inclusions, which are fairly easy to see under with a 10X magnification, and can be seen with the naked eye.

L1, L2, and L3-Imperfect - These stones have inclusions ranging from eye visible to very easily seen to the naked eye.

L4 - Opaque - Not transparency.