I asked the different between both before.
Granite - original stone
Quarts - processed stone
Main different is Quartz after processed will become strong in resistent to scratches and more compressed (if you zoom in with microscope you see no gap). Granite is very strong by itself but still prone to scratches. Stone by itself have small gap which cant be see with our bare eyes and this hole will be fill with gems or dirt which we cannot see or clean.