Phaneritic Texture Igneous Rock

The texture is often found in extrusive aphanitic or glassy igneous rock.

Phaneritic texture igneous rock. Intrusive igneous rocks thus have coarse grained or phaneritic textures with visible crystals and extrusive igneous rocks have fine grained or aphanitic texture. There are nine main types of igneous rock textures. The vesicles are small cavities formed by the expansion of bubbles of gas or steam during the solidification of the rock. Each kind of texture has a variety of different characteristics that make them unique.

Such rocks are termed intrusive rocks. In contrast the crystals in an aphanitic rock are too small to be seen with the naked eye phaneritic texture forms when magma deep underground in the plutonic environment cools slowly giving the crystals time to grow. A good rule of thumb is that fine grained or aphanitic rocks are dull appearing while phaneritic rocks are brighter or shinier of course be careful of a glassy rock like obsidian. Basalt is a classic fine grained aphanitic extrusive igneous rock.

Phaneritic vesicular aphanitic porphyritic poikilitic glassy pyroclastic equigranular and spinifex. As magma cools slowly the minerals have time to grow and. The slow cooling process allows crystals to grow large giving the intrusive igneous rock a coarse grained or phaneritic texture. Properties of igneous rock textures.

Phaneritic rock phaneritic rock is igneous rock with large identifiable crystals of roughly equal size. But dark rocks like gabrro are more problematic. Igneous textures include the rock textures occurring in igneous rocks igneous textures are used by geologists in determining the mode of origin igneous rocks and are used in rock classification. 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.

Such crystals are characteristic of rocks which solidified far below the surface so that the cooling was slow enough to enable the large crystals to grow. The individual crystals in phaneritic texture are readily visible to the unaided eye. Vesicular texture is a volcanic rock texture characterised by or containing many vesicles. Phaneritic phaner visible textures are typical of intrusive igneous rocks these rocks crystallized slowly below the earth s surface.

For the more felsic rocks like granite phaneritic texture is rarely misidentified. There are six main types of textures. Phaneritic aphanitic porphyritic glassy pyroclastic and pegmatitic.