IF	Internally Flawless - Free from inclusions under 10x magnification
VVS	Very, Very Slightly Included - Very few inclusions visible under 10x magnification and very difficult to find
VS	Very Slightly Included - Inclusions visible under 10x magnification and found fairly easily by an expert
SI	Slightly Included - Inclusions clearly visible under 10x magnification (and possibly to the naked eye), but not affecting stone brilliance appreciably
I	Included - Inclusions clearly visible to naked eye but not affecting stone brilliance appreciably
P	Pique - Inclusions clearly visible to naked eye and have a significant impact on brilliance