Alkali Feldspar Granite Composition

Alkali feldspar granite contains between 20 60 quartz.

Alkali feldspar granite composition. Scituate igneous suite alkali feldspar granite gray to pink medium to coarse grained porphyritic to subporphyritic alkali feldspar granite phenocrysts of perthite. The streak of alkali feldspar granite is white. Alkali feldspar granite is available in black grey orange pink white colors. Alkali fledspar granite is an intrusive igneous rock which is very hard crystalline and is visibly homogeneous in texture and forms by melting of continental rocks.

Granite s s is a plutonic rock with a simple felsic mineralogy of quartz alkali feldspar plagioclase with more than 20 quartz and plagioclase representing 10 to 65 vol of total feldspar. Less than that amount would designate the rock as a granite. The perthitic textures in the alkali feldspars of many granites can be seen with the naked eye. The streak of a rock is the color of powder produced when it is dragged across an unweathered surface.

In addition to granite intrusive rocks with over 20 vol of quartz are commonly referred to as. More than 90 of the total feldspar content is in the form of alkali feldspar. Contains perthite quartz and accessory biotite hornblende and lesser riebeckite aegerine zircon allanite sphene fluorite and opaque minerals. Formation of alkali feldspar granite is explained below.

Search photos of peralkaline alkali feldspar granite edit add synonym add sub type rock clear cache a term that may be used for a variety of alkali feldspar granite that contains alkali pyroxene and or amphibole. Feldspar feldspar chemical composition. The principal constituent of granite is feldspar. As shown in the qapf diagram alkali feldspar granite contains between 20 60 quartz.

Alkali feldspar granite also known as red granite is a felsic igneous rock and a type of granite rich in the mineral potassium feldspar. And t silicon si and aluminum al with a si al ratio ranging from 3 1 to 1 1. Both plagioclase feldspar and alkali feldspar are usually abundant in it and their relative abundance has provided the basis for granite classifications. In most granite the ratio of the dominant to the subdominant feldspar is less than two.

More than 90 of the total feldspar content is in the form of alkali feldspar. Less quartz content would lead to quartz alkali feldspar syenite. Less quartz content would lead to quartz alkali feldspar syenite. Along with alkali feldspar granite formation also learn about alkali feldspar granite composition and transformation in the next section.