It is impractical to try and explain in words. "Some, but not too much" doesn't really tell you anything. If you post a photograph we could tell you if yours is normal or not.
If not enough of the quartz is exposed, they can do an acid wash to expose more. Depending on where you are in the process, the builder might have an acid wash scheduled but not done yet.
As PoolGuyNJ hints at, how the water chemistry is maintained and how often the surface is brushed over the first three to six weeks is very important to the final appearance.