Granite is an igneous rock formed from the slow crystallization of magma below Earth’s surface. It’s mainly composed of quartz along with alkali feldspars, plagioclase feldspars, and other mineral impurities present during its formation. It ranks 6 on the Mohs mineral hardness scale. Because granite is highly durable and stain-resistant, granite countertops are a popular choice in the kitchen. Regular sealing is required though to close up its naturally porous surface.