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"Imperial Porphyry" from the Red Sea Mountains of Egypt A waterworn cobble of porphyry Rhyolite porphyry from Colorado; scale bar in lower left is 1 cm (0.39 in). Porphyry (/ ˈ p ɔːr f ə r i / POR-fə-ree) is any of various granites or igneous rocks with coarse-grained crystals such as feldspar or quartz dispersed in a fine-grained silicate-rich, generally aphanitic matrix or groundmass.
Porphyria / p ɔːr ˈ f ɪr i ə / is a group of disorders in which substances called porphyrins build up in the body, adversely affecting the skin or nervous system. [1] The types that affect the nervous system are also known as acute porphyria, as symptoms are rapid in onset and short in duration. [1]
Porphyritic texture in a granite. This is an intrusive porphyritic rock. The white, square feldspar phenocrysts are much larger than crystals in the surrounding matrix; eastern Sierra Nevada, Rock Creek Canyon, California. A porphyritic volcanic sand grain, as seen under the petrographic microscope. The large grain in the middle is of a much ...
normally occurring as porphyritic dikes; containing matrix restricted feldspars and/or feldspathoids if present; biotite or phlogopite is an essential mineral phase; commonly extensively hydrothermally altered; may contain primary calcite, zeolites and other more typically hydrothermal minerals
A subvolcanic rock, also known as a hypabyssal rock, is an intrusive igneous rock that is emplaced at depths less than 2 km (1.2 mi) within the crust, and has intermediate grain size and often porphyritic texture between that of volcanic rocks, which are extrusive igneous rocks, and plutonic rocks, which form much deeper in the ground. [1]
Rhomb porphyries are an unusual variety with gray-white porphyritic rhomb shaped phenocrysts embedded in a very fine grained red-brown matrix. The composition of rhomb porphyry places it in the trachyte - latite classification of the QAPF diagram. Latite is found, for example, as lavas in Bulgaria [3] and as intrusive laccoliths and sills in ...
Porphyry (geology), an igneous rock with large crystals in a fine-grained matrix, often purple, and prestigious Roman sculpture material; Shoksha porphyry, quartzite of purple color resembling true porphyry mined near the village of Shoksha, Karelia, Russia; Porphyritic, the general igneous texture of a rock with two distinct crystal ...
Aphanites are commonly porphyritic, having large crystals embedded in the fine groundmass, or matrix. The larger inclusions are called phenocrysts . They consist essentially of very small crystals of minerals such as plagioclase feldspar , with hornblende or augite , and may contain also biotite , quartz , and orthoclase .