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Porphyritic is an adjective used in geology to describe igneous rocks with a distinct difference in the size of mineral crystals, with the larger crystals known as phenocrysts. Both extrusive and intrusive rocks can be porphyritic, meaning all types of igneous rocks can display some degree of porphyritic texture.
Also called Indianite. A mineral from the lime-rich end of the plagioclase group of minerals. Anorthites are usually silicates of calcium and aluminium occurring in some basic igneous rocks, typically those produced by the contact metamorphism of impure calcareous sediments. anticline An arched fold in which the layers usually dip away from the fold axis. Contrast syncline. aphanic Having the ...
"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.
Normally the term phenocryst is not used unless the crystals are directly observable, which is sometimes stated as greater than 0.5 mm (0.020 in) in diameter. [1] Phenocrysts below this level, but still larger than the groundmass crystals, are termed microphenocrysts. Very large phenocrysts are termed megaphenocrysts.
This list of Latin and Greek words commonly used in systematic names is intended to help those unfamiliar with classical languages to understand and remember the scientific names of organisms. The binomial nomenclature used for animals and plants is largely derived from Latin and Greek words, as are some of the names used for higher taxa , such ...
This is a list of terms and symbols used in scientific names for organisms, and in describing the names. For proper parts of the names themselves, see List of Latin and Greek words commonly used in systematic names. Note that many of the abbreviations are used with or without a stop.
Born in the purple, Porphyrogénnētos , Byzantine term for the children of emperors, after a supposed porphyry-lined birthing room in the palace; Article titles containing the text "Porphyr" Porfirio (disambiguation), various uses, including a Spanish surname; Porfiry, a Russian given name; Tyrian purple or Porphyra, a purple-red natural dye
Occasionally some individual crystals (phenocrysts) are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic texture is known as a granite porphyry. Granitoid is a general, descriptive field term for lighter-colored, coarse-grained igneous rocks.