Granite (from the Latin granum grain, in reference to the texture of the rock) is a common type of igneous rock or magmatic, intrusive or plutonic rock of fine non-metamorphic, medium or coarse grain, composed essentially of the minerals quartz, mica and feldspar, having Such as mineral mica (usually present), hornblende, zircon and other minerals. It is usually found on continental plates of the Earth’s crust.
The granite is almost always solid (without internal structure), hard and resistant, being by these qualities used as stone for the civil construction. The average granite density is between 2.65 and 2.75 g / cm 3.
Its melting temperature is 1215 – 1260 ° C.
The mineralogical composition of the granites is defined by very varied associations of quartz, feldspar, micas (biotite and / or moscovite), amphibole (mainly horneblende), pyroxenes (augite and hyperstena) and olivine. Some of these constituents may be absent in certain mineralogical associations, noting several other accessory minerals in much smaller proportions. Quartz, feldspar, micas and amphibole are the dominant minerals in granite and related rocks.
The feldspars (microcline, orthoclase and plagioclase) are the main determinants of the chromatic pattern of the silica rocks, giving the reddish, pinkish and creamy-gray colorations to these rocks.