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Phaneritic (phaner = visible) textures are typical of intrusive igneous rocks, these rocks crystallized slowly below Earth's surface. As magma cools slowly the minerals have time to grow and form large crystals. The minerals in a phaneritic igneous rock are sufficiently large to see each individual crystal with the naked eye.
Close-up of granite, a phanerite rock, from Yosemite National Park in California, U.S. Phaneritic diorite from Massachusetts. A phanerite [1] is an igneous rock whose microstructure is made up of crystals large enough to be distinguished with the unaided human eye. In contrast, the crystals in an aphanitic rock are too fine-grained to be ...
In geology, texture or rock microstructure [1] refers to the relationship between the materials of which a rock is composed. [2] The broadest textural classes are crystalline (in which the components are intergrown and interlocking crystals), fragmental (in which there is an accumulation of fragments by some physical process), aphanitic (in which crystals are not visible to the unaided eye ...
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Macrocrystalline or phaneritic texture is common in intrusive igneous rocks that cooled slowly enough for crystal growth. Pegmatites are noted for their large crystal size. The texture is also commonly found in late-diagenetic dolomite, recrystallized limestone, and some types of anhydrite. [2]
For phaneritic felsic rocks, the QAPF diagram should be used, and a name given according to the granite nomenclature. Often the species of mafic minerals is included in the name, for instance, hornblende-bearing granite, pyroxene tonalite or augite megacrystic monzonite , because the term "granite" already assumes content with feldspar and quartz.
Intrusive rocks are characterized by large crystal sizes, and as the individual crystals are visible, the rock is called phaneritic. [8] There are few indications of flow in intrusive rocks, since their texture and structure mostly develops in the final stages of crystallization, when flow has ended. [9]
Gabbro (/ ˈ ɡ æ b r oʊ / GAB-roh) is a phaneritic (coarse-grained and magnesium- and iron-rich), mafic intrusive igneous rock formed from the slow cooling magma into a holocrystalline mass deep beneath the Earth's surface. Slow-cooling, coarse-grained gabbro is chemically equivalent to rapid-cooling, fine-grained basalt.