Asked in Geology
What is perthitic texture?
A perthitic texture is an intimate intergrowth of sodic and potassic feldspar resulting from subsolidus exsolution (unmixing of two minerals). Strictly speaking a perthite has blebs or irregular lamellae of sodic feldspar within potassic alkali feldspar, however, the term perthite is often used to describe all types of exsolution in the feldspars. An antiperthite is an intergrowth arising due to exsolution where potassic feldspar is present as blebs or lamellae within a sodic feldspar. The term mesoperthite is used when sodic and potassic...
Asked in Geology, Igneous Rock
How do you identify types of igneous rocks?
Igneous rocks are identified by first looking at the color index. Felsic igneous rocks contain mostly potassium feldspar. Intermediate igneous rocks contain mostly plagioclase feldspar. Mafic igneous rocks contain pyroxene, olivine, and plagioclase feldspar. Ultra mafic igneous rocks contain mostly olivine. Then igneous rocks are identified based on texture. For example, the texture of igneous rocks can be aphanitic, pegmatitic, phaneritic, glassy, vesicular, etc. ...
Asked in Geology, Rocks and Minerals, Igneous Rock
What minerals are found in granite?
Granite is composed of varying amounts of the must have minerals quartz, potassium feldspar (orthoclase feldspar, penis, sanidine feldspar, microcline feldspar), plagioclase feldspar, and may but does not have to have biotite, muscovite and hornblende. ...
Asked in Geology
What is the dominant feldspar in granite?
Granite contains plagioclase feldspar and potassium feldspar. It really depends on the composition of the magma from which it forms. If the granite has a lot of pink in it, chances are it is potassium feldspar (K-Spar). If it is dominated by white, then the feldspar is probably plag. ...
Does Gabbro and granite have a similar mineral composition and texture?
the textures are similar yes but gabbro is made up of calcite and olivine while granite contains biotite mica, feldspar, and quartz. ...