Emeralds are a very rare and valuable gem...
Color and Crystallinity are the two most important C’s in the emeralds...
Emeralds are green but have secondary color...My favorite green color is the 7up bottle green color that has a little darkness to them...A tone of 7-8 in a 1-10 scale 1 being light and 10 being very dark green.
As far as clarity is concerned. Emeralds typically have a lot of inclusions. So to find an emerald that is VVS or VS is quite rare.