Alkali Feldspar Granite Composition

Less quartz content would lead to quartz alkali feldspar syenite.

Alkali feldspar granite composition.

Alkali feldspar granite also known as red granite is a felsic igneous rock and a type of granite rich in the mineral potassium feldspar. As shown in the qapf diagram alkali feldspar granite contains between 20 60 quartz. More than 90 of the total feldspar content is in the form of alkali feldspar. The streak of a rock is the color of powder produced when it is dragged across an unweathered surface.

Alkali feldspar granite contains between 20 60 quartz. The principal constituent of granite is feldspar. Perthite is a typical texture in alkali feldspar due to exsolution of contrasting alkali feldspar compositions during cooling of an intermediate composition. All the rock forming feldspars are aluminosilicate minerals with the general formula at4o8 in which a potassium sodium or calcium ca.

And t silicon si and aluminum al with a si al ratio ranging from 3 1 to 1 1. 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. 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. 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. Alkali feldspar granite is available in black grey orange pink white colors. The perthitic textures in the alkali feldspars of many granites can be seen with the naked eye. Less than that amount would designate the rock as a granite.

Both plagioclase feldspar and alkali feldspar are usually abundant in it and their relative abundance has provided the basis for granite classifications. Scituate igneous suite alkali feldspar granite gray to pink medium to coarse grained porphyritic to subporphyritic alkali feldspar granite phenocrysts of perthite. Formation of alkali feldspar granite is explained below. In most granite the ratio of the dominant to the subdominant feldspar is less than two.

Feldspar feldspar chemical composition. In addition to granite intrusive rocks with over 20 vol of quartz are commonly referred to as. Contains perthite quartz and accessory biotite hornblende and lesser riebeckite aegerine zircon allanite sphene fluorite and opaque minerals. 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.