Granite and feldspar. The term "granitic" means granite-like and is applied to granite and a group of intrusive igneous rocks with similar textures and slight variations in composition and origin. These rocks mainly consist of feldspar, quartz, mica, and amphibole minerals, which form an interlocking, somewhat equigranular matrix of feldspar and quartz with scattered darker biotite mica and amphibole (often hornblende) peppering the lighter color minerals. Occasionally some individual crystals (phenocrysts) are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic texture is known as a granite porphyry. Granitoid is a
Granite Island (Michigan) is made available to the NMU English Department for creative writing retreats. 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