Are there different grades of granite?

Yes. There is #1 or First Grade and then there is Commercial Grade. There are a wide variety of reasons for grading granite as commercial grade rather than #1, but the most common reason is that it does not fit within the color parameters of the quarries control sample. It is not necessarily a less desirable piece of granite, but it is generally more unique in color and/or pattern and therefore more difficult to match should that become necessary.