Granite is a very hard igneous rock created from what was once liquid magma. It is found in the continental crust, especially in North America as part of Canadian Shield.
Common minerals that are found in granite include quartz, feldspar and mica. Other minerals such as magnetite, apatite and zircon are also in granite. The feldspar that is found in granite is radioactive. The released radiation causes normally clear quartz crystals to turn black. The color of the feldspar also determines the color of the granite. These can range from gray or pink to darker colors.
Granite is a common building material for construction because of its density, variation in color and its ability to be polished.