Granite general, descriptive field term for lighter-colored, coarse-grained igneous rocks. Petrographic examination is required for identification of specific types of granitoids. The extrusive igneous rock equivalent of granite is rhyolite. Granite is nearly always massive (i.e., lacking any internal structures), hard, and tough. These properties have made granite a widespread construction stone throughout human history. The average density of granite is between , its compressive strength usually lies above 200 MPa, and its viscosity near STP is 3–6·10 Pa·s. The melting temperature of dry granite at ambient pressure is ; it is strongly reduced in the presence of water, down to
Granite Island (Michigan) Granite Island (Michigan) Granite Island is a island in Lake Superior located about northwest of Marquette in the Upper Peninsula of the U.S. state of Michigan. Built upon it is the Granite Island Lighthouse, also known as Granite Island Light Station, "one of the oldest surviving lighthouses on Lake Superior". It is part of Marquette Township, in Marquette County. The island is granite rock that rises nearly perpendicularly to above the surface of Lake Superior, surrounded by deep water. The Native Americans called the island "Na-Be-Quon". That apparently meant something like 'vessel'. They called a steam ship an "ishcoda nabequon".