It is very rare (nearly unheard of) to find a ruby with natural perfect clarity. 99.9% of rubies are heat treated or irradiated to improve clarity, diminishing the appearnace of the many inclusions. The most common form of inclusion in ruby is white whispy wavy deposits of rutile.
|Terrible Clarity: This ruby is very included: we can see large white inclusions inside it and it has an overall opaque appearance due to many small inclusions that make it cloudy. Rubies of this clarity are not precious and should never be very expensive||Poor Clarity: This ruby is not very clear either. It has better clarity than the first though, because there are no obvious large inclusions and the stone is still more transparent than opaque. However, it is not clear enough to be faceted.||Typical Clarity: A ruby like this is what is most commonly available in jewelry. It is too cloudy or included to see completely into the stone. However, it is clear enough that we are able to see some light and sparkle. A ruby of this clarity can be valuable if it is also very large and of excellent color.||Very Good Clarity: In a natural ruby, this is as good as it gets. A ruby this clear is very rare. It is not perfectly clear: there are some visible inclusions, but in all, the clarity alone makes this ruby very valuable.|