This problem does not occur often, but it does tend to occur more commonly in new construction and with these granite varieties / colors:
Santa Cecelia
Giallo Vicenza
Giallo Veneziano
New Venetian Gold
You can read more questions and answers about this issue on our page about grit on granite countertops, however, there are a couple possible causes:
A grit on a countertop can occur after a newly-grouted backsplash where grout particles are falling onto the surface. This will cease rather quickly though after all remaining loose particles fall off.
Unfortunately, most often, the reason is a poor-quality slab of granite that was not "resined". On many granite slabs, a resin is applied to fill surface voids, blemishes and make the slab stronger. This does not change the basic appearance of the granite and is a common and accepted practice. In many cases, a gritty slab is one that was not resined.
This does not mean that every slab of the above colors will be bad... not at all. In fact, Santa Cecelia is an extremely popular granite and installed all the time without issue.
Remember we are dealing with a natural stone, so there can be a lot of variation in color, pattern, and the quality of the stone. The surface of some slabs cannot be finished very well. That is to say that some granite varieties will polish to a higher shine than others and some slabs are very difficult to polish well and may even have an uneven finish or rough areas.
Such slabs should not be installed, but they do sneak into the marketplace. Sometimes builders use cheaper slabs, which are more prone to problems. Although in fairness, it can be difficult to detect this particular problem when the slab is stored on edge in the warehouse. It may look and feel fine, but then after installation, the fine grit is apparent.
Unfortunately again, there is typically no solution to this problem except replacement or have a resin applied. Repolishing the granite won't generally improve it. The granite slab was finished or polished as best as it possibly can be on big specialized machines at the factory. Once installed in your home it can only be re-polished with hand-held tools. This is effective for many types of repairs, however, if the polishing machine could not produce a good finish, then chances are very slim that re-polishing in your home will yield better results.