Metamorphic Granite Rock Composed Of Mica And Quartz

Examples of metamorphic rocks.

Metamorphic granite rock composed of mica and quartz. A metamorphic rock choose one. Is always composed of the same minerals as its protolith. Slate is another common metamorphic rock that forms from shale. It is a high grade metamorphic rock in which mineral grains recrystallized under intense heat and pressure.

Granite is an igneous rock that forms when magma cools relatively slowly underground. Granite is a light colored rock made of quartz feldspars mica and small amounts of hornblende. Mica schist the most common schistose rock and the second most common metamorphic rock is composed mostly of mica usually biotite or muscovite and smaller amounts of quartz. May have preferred mineral orientation caused by differential stress.

When granite is subjected to intense heat and pressure it changes into a metamorphic rock called gneiss. Quartzite is a nonfoliated metamorphic rock composed almost entirely of quartz. The crystals of all these minerals are randomly arranged. This alteration increased the size of the mineral grains and segregated them into bands a transformation which made the rock and its minerals more stable in their metamorphic environment.

May develop a texture of noninterlocking grains. It is usually composed primarily of the minerals quartz feldspar and mica. It forms when a quartz rich sandstone is altered by the heat pressure and chemical activity of metamorphism. Cannot be formed below 1 200 c.

Depending on the feldspar present granite may be pink dark gray or light gray. At the highest grades of metamorphism minerals begin to segregate into separate bands. Granite can be metamorphosed into a rock called gneiss pronounced like nice. Composed of quartz feldspar and mica.

Gneiss can form in several different ways. The original rock is subjected to heat temperatures greater than 150 to 200 c and pressure 100 megapascals 1 000 bar or more causing profound physical or chemical change the protolith may be a sedimentary igneous or existing metamorphic rock. These conditions recrystallize the sand grains and the silica cement that binds them together. Its composition is equal to that of granite but forms alternating layers of clear and dark minerals.

Gneiss has about the same mineral composition as granite but the pressure of metamorphism causes the. A coarse grained and generally igneous rock of even texture and light color composed chiefly of quartz and feldspars. The layering in a rock in which bands or lenses of granular minerals quartz and feldspar alternate with bands or lenses in which platy mica or elongate amphibole minerals predominate. It usually contains small quantities of mica or hornblende and sometimes minor accessory minerals.

Its basic component is calcium carbonate.