Good clarity is still desirable, however to the extent that light is able to play inside the stone, and it is transparent. While perfect clarity is not necessary to make an emerald exceptionally valuable, an absolutely opaque emerald is not worth much: in fact even the best color of emerald, if it is completely opaque, can no longer be considered precious.
Here are some illustrations of how different levels of clarity appear in emerald:
|Terrible Clarity: These emeralds have so many inclusions (cracks, whispy white particles, etc.) that we cannot see into the stones at all. These are not "gem quality" emeralds for this reason. They are not very valuable||Poor Clarity: This emerald cabochon is not very transparent: light does not play inside the stone because of many very small inclusions.||Typical Clarity: Most emeralds you find in jewelry look more or less like this. They are very include_onced but transparent enough to catch some light now and then and give you a little bit of sparkle.||Perfect Clarity: Here is an example of a perfectly clear emerald. We can see all the way into the stone: there is no "haziness" nor visible inclusions. Good clarity allows the stone to be faceted: maximizing reflected light and sparkle.|