I have an existing exposed aggregate patio that is a year old. I recently had an additional exposed aggregate patio poured adjacent to the existing patio. I was told by the contractor that the colors would be close but not an exact match. When they did not match at all, I was told to wait a few weeks as the colors could change. Well, they still do not match-and the contractor basically said there is nothing he can do. Can I paint or stain the older aggregate and still be able to see the aggregate stones? Help.