What Is The Aphanitic Form Of Granite

Igneous rocks form from which of these processes.

What is the aphanitic form of granite.

Granite is an aphanitic rock that form from lava. Aphanitic extrusive igneous rocks therefore have coarse grained intrusive counterparts with the same chemical and mineral composition. When extrusive rocks make contact with the atmosphere they cool quickly so the minerals do not have time to form large crystals. There are nine main types of igneous rock textures.

Phaneritic vesicular aphanitic porphyritic poikilitic glassy pyroclastic equigranular and. The igneous rock shown on the image below is. Intrusive igneous rocks thus have coarse grained or phaneritic textures with visible crystals and extrusive igneous rocks have fine grained or aphanitic texture. Crystallization of a magma or lava.

Specimen is about 4 5 x 3 5 x 3 5 centimeters. This includes the size and quality and interrelations of its grains and the fabric they form. Aphanitic a not phaner visible rocks in contrast to phaneritic rocks typically form from lava which crystallize rapidly on or near earth s surface. For example the silica rich extrusive rock rhyolite common in continental volcanic regions is the fine grained equivalent of intrusive granite.

The specimen shown here is about two inches five centimeters across. Larger scale features such as fractures and layering are considered rock structures in comparison. Andesitic rocks or intermediate rocks andesite is a medium gray fine grained rock of volcanic origin named after the andes mountains but is abundant in all volcanic regions associated with subduction zones where crust is sinking and partially. Which rock consists of mafic minerals and has a phaneritic texture.

Volcanic glass called obsidian forms when lava is quenched and solidified so quickly that the silicate ions in the melt form no orderly atomic structure. Pegmatite is an igneous rock composed almost entirely of crystals that are over one centimeter in diameter. Examples of phaneritic igneous rocks are gabbro diorite and granite. A crystal of imperial topaz on an albite matrix from a pocket in the katlang pegmatite of pakistan.

Look it up now. Rhyolite aphanitic small crystals of felsic minerals with the same composition of granite.