Gneiss is a coarse to medium grained banded metamorphic rock formed from igneous or sedimentary rocks during regional metamorphism. Banded gneisses called migmatites are composed of alternating light colored layers of granite or quartz feldspar and dark layers rich in biotite.
Granite is a purely natural stone that comes directly from stone quarries and is then cut into thin slabs, polished, and fabricated into countertops. So-called quartz countertops are engineered stone products that may contain a large percentage of natural quartz but may also include other minerals.
