Stone Selection: Granite Slabs
What is commercially known as granite includes true granites and gabbro as well as gneiss stones. Granite and gabbro are igneous rock that started out as molten magma and has slowly cooled. The primary difference between a granite and a gabbro is the silica content (gabbro has less silica than granite). Gneiss stones on the other had while resembling granite in it's crystalline structure is actually a metamorphic stone that has metamorphosed from a schist. These differences (how they were formed, mineral content, density, porosity, etc) are why not all "granite" countertops perform the same. However, with proper care & cleaning this should not be an issue in most cases. It may be interesting to note that lighter colored gneiss tend to be less dense than darker stones and true granites. Most of the stone commercially known as a granite are quite hard regardless of their density and will be fairly scratch resistant.