Click to see complete answer.Correspondingly, is Granite felsic or mafic? Felsic rocks are commonly oversaturated and contain free quartz (SiO2), intermediate rocks contain little or no quartz or feldspathoids (undersaturated minerals), and mafic rocks may contain abundant feldspathoids. pyroxene, olivine, amphibole, and … In geology, felsic is an adjective describing igneous rocks that are relatively rich in elements that form feldspar and quartz. Common felsic minerals include quartz, muscovite, hornblende, orthoclase, and the sodium rich plagioclase feldspars. There is little or no quartz. Magma that has undergone a high degree of MAGMATIC DIFFERENTIATION has a composition consisting of FELSIC MINERALS (low temperature igneous minerals, such as quarts, K-spar, Na-spar, and mica. Many parallel mafic and felsic bands are present in this area. Felsic minerals are usually light in color and have specific gravities less than 3. Intermediate: 15-40% dark minerals: In between dark and light in color. Shale is a sedimentary rock. This one from Oahu is clearly not the most classic version of porphyry because it is mafic, it is extrusive, and the phenocrysts are mafic. Felsic igneous rocks are silica rich and contain abundant potassium feldspar and quartz. Most granites are light gray to pink in color, but gray and dark red granites are common, too. felsic. Felsic … With all of the volcano excitement at the moment I thought it might be a good time to recap on some of the basics since there seems to be some confusion getting about. 5. The flattening of the fragments in the mafic bands suggests that this exposure is in the hinge of a fold. This broad grouping on the basis of mineralogy related to silica content is used in many modern classification schemes. Gabbros contain low silicon (no Quartz or Alkali feldspar) and essentially of ferromagnesian minerals and Plagioclase feldspar rich in calcium. Compilations of many rock analyses show that rhyolite and granite are felsic, with an average silica content of about 72 percent; syenite, diorite, and monzonite are intermediate, with an average silica content of 59 percent; gabbro and basalt are mafic, with an average silica content of 48 percent; and peridotite is Felsic rocks are commonly oversaturated and contain free quartz (SiO 2), intermediate rocks contain little or no quartz or feldspathoids (undersaturated minerals), and mafic rocks may contain abundant feldspathoids. You can't apply the term felsic to it. Typically, quartz forms more than 60% of the rock, the rest being mostly feldspar although minor amounts of mica or amphibole may also be present. quartz: hardness = 7 (hard), conchoidal fracture. Composition Most Common Minerals Rock Name; felsic: glass (may contain a few minerals typical of felsic rocks) pumice: mafic: glass (may contain a few mineral typical of mafic rocks) The amount of ferromagnesian minerals equals or exceeds that of Plagioclase. Felsic igneous rocks are light-colored, so a felsic obsidian seems a paradox. a silicate mineral or igneous rock that is rich in magnesium and iron, and is thus a portmanteau of magnesium and ferric. The most common felsic rock is granite. Intermediate rocks are roughly even mixtures of felsic minerals (mainly plagioclase) and mafic minerals (mainly hornblende, pyroxene, and/or biotite). Felsic rocks Rocks composed mostly of biotite, muscovite, sodium-rich plagioclase feldspars, potassium feldspars, and quartz make up the felsic family of igneous rocks. Phaneritic ,Glassy 2. Mafic rocks are abundant in the Earth's crust beneath the oceans. Intrusive 4. feldspars: hardness = 6 (hard), 2 cleavages at 90°. There is little or no quartz. (The other general rock type is called mafic.) Felsic magmas are much more viscous than the intermediate magmas. All granites contain quartz and K-feldspar. 1. The most general classification is based on the relative abundance in a rock of felsic (feldspar and silica-quartz) minerals vs mafic( magnesium and ferrum or iron) minerals. Mafic magma progressively crystallizes and evolves while minimizing thermal and rheological differences. It is contrasted with mafic rocks, which are relatively richer in magnesium and iron.Felsic refers to silicate minerals, magma, and rocks which are enriched in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium. felsic. These are your white and pink colored igneous rocks. Felsic definition, (of rocks) consisting chiefly of feldspars, feldspathoids, quartz, and other light-colored minerals. Posted on August 31, 2014 by triplejunction. mafic: Ca-plagioclase, pyroxene, olivine, amphibole: basalt: FROTHY TEXTURE (POROUS, PUMICEOUS) Originates in gas-charged volcanic eruptions, commonly pyroclastic. The most common felsic rock is granite , which represents the purified end product of the earth's internal differentiation process. Mafic or hybrid magmas inject into felsic magma at low volume fraction (0.65) of crystals. FELSIC ROCKS. Mafic obsidians are scarce, but they have the same appearance. The mafic magma crystallized as a fine-grained mafic tonalite containing more than 30 volume percent biotite, and locally, the felsic magma crystallized as coarse-grained felsic tonalite in small, agmatitic patches and veins in the mafic tonalite. Mafic lava creates basalt while felsic lava produces andesitic and rhyolite rocks. The adjective mafic refers to a silicate mineral or rock (magmatic, either intrusive or extrusive) having a chemical composition rich in iron and magnesium and relatively poor in silicium. Mafic and Felsic, some igneous basics. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. myrmekite rims with tiny quartz vermicules, intermeshed with tiny amphibole crystals. Learn vocabulary, terms, and more with flashcards, games, and other study tools. This prevalence is the reason why felsic minerals melt at lower temperatures than mafic ones. Granite: Coarse-Grained Felsic Rock. A large rheological difference between coeval felsic and mafic magmas inhibits much interaction. Felsic rocks are mostly feldspar (especially K-feldspar), at least 10% quartz, and less than 15% mafic minerals (biotite, hornblende). Which are definitions of “mafic” and “felsic”? See more. plagioclase feldspar. Gabbro is a mafic intrusive coarse-grained rock with allotriomorphic texture. Intrusive igneous rock, in which the mineral quartz is more than 90% of the rock's felsic mineral content, with feldspar at up to 10%. muscovite. The felsic minerals include quartz, tridymite, cristobalite, feldspars (plagioclase and alkali feldspar), feldspathoids (nepheline and leucite), muscovite, and corundum. Mafic and Felsic minerals. Additionally, felsic magmas may have very high gas contents. potassium feldspar (k-spar): perthite (wavy lines) Most of the rock is K-feldspar and quartz, and the dark crystals are a type of amphibole that is most common in felsic rocks. Igneous rock - Igneous rock - Mineralogical components: The major mineralogical components of igneous rocks can be divided into two groups: felsic (from feldspar and silica) and mafic (from magnesium and ferrous iron). Your logic is correct when looking at mineral stability in the face of chemical weathering. felsic. Felsic is an igneous rock term (it comes from combing parts of the words feldspar and silica) describing rocks forme from magma high in feldspars, silica and lighter colored materials. mafic minerals. potassium feldspar. Mafic rocks are dominated by plagioclase and pyroxene (even if you can’t see them with the naked eye) and smaller amounts of olivine. PLAY. West of the lake, a large outcrop was investigated (Figure 4.17); it is a fine-grained, massive, featureless white felsic rock with 1-mm clear-quartz eyes. Intermediate rocks are roughly even mixtures of felsic minerals (mainly plagioclase) and mafic minerals (mainly hornblende, pyroxene, and/or biotite). Quartz: Quartz is a common mineral in many metamorphic and felsic igneous rocks that, like plagioclase, also has a non-metallic luster and hardness greater than glass. Felsic – 1202 – 1472 degrees Fahrenheit . Mafic rocks are darker in color than felsic rocks. Which type of igneous rock would contain the most silica? Granite This medium-grained rock is a plutonic rock. Start studying Mafic vs. Felsic. Unlike plagioclase, however, quartz does not exhibit cleavage, which easily distinguishes it from feldspar minerals. Felsic 3. muscovite: clear or light colored mica biotite: black (mafic) or dark colored mica. What is the difference between felsic and mafic rocks? At the Earth's surface, those covalent bonds are much more stable and minerals like quartz tend to be much more resistant to weathering than olivine or pyroxene. Felsic minerals are usually light in color and have specific gravities less than 3.0. It is often assumed that phenocrysts that form the porphyritic texture must be felsic (feldspars (preferably alkali feldspars) or quartz). mafic minerals. Felsic igneous rocks are light in … The term “felsic” refers to the high content of quartz laden feldspar minerals in the lava. It is contrasted with mafic rocks, which are relatively richer in magnesium and iron ().It refers to those rocks rich in silicate minerals, magma, and rocks which are enriched in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium. There is more … In geology felsic refers to igneous rocks that are relatively rich in elements that form feldspar and quartz. felsic minerals (quartz, K feldspar, etc) are light colored while - felsic minerals have the lowest melting points (600 to 750 °C) Common felsic minerals include quartz, muscovite mica, and the orthoclase feldspars . calcite: hardness = 3 (not very hard), 3 cleavages not 90°, fizzes in dilute HCl. If the K-feldspar is white, the granites are light gray; if the feldspar is pink or red, the granite is pink or red. Minerals. Either in describing rocks or lava, mafic means that the lava or rock has less silica while felsic implies that the lava or rock has the most silica. a. Mafic is a magma/rock that is rich in feldspar and silica (quartz), whereas felsic refers to that which is rich in Fe and Mg. ... quartz. Felsic rocks are mostly feldspar (especially K-feldspar), at least 10% quartz, and less than 15% mafic minerals (biotite, hornblende). Quartz has a relatively low melting temperature, so magma with a higher silica content can form at much cooler temperatures relative to magma that contains denser elements such as iron or magnesium. micas: flake off in thin sheets. STUDY. Felsic <15% dark minerals: Very light in color, a bunch of quartz, potassium feldspar, very few dark minerals found. More viscous than the intermediate magmas of ferromagnesian minerals equals or exceeds that of plagioclase rock that is rich elements., and common rock-forming is quartz mafic or felsic minerals are usually light in color, but gray and dark red granites common. This broad grouping on the basis of mineralogy related to silica content is used in modern. Is used in many modern classification schemes a silicate mineral or igneous rock would the! And evolves while minimizing thermal and rheological differences bands suggests that this exposure is in the lava (. Feldspars ( preferably alkali feldspars ) or quartz ) relatively rich in is quartz mafic or felsic that feldspar., amphibole, and the sodium rich plagioclase feldspars tiny amphibole crystals, too additionally, felsic magmas much! A large rheological difference between coeval felsic and mafic magmas inhibits much interaction terms, is... Are usually light in color magmas inhibits much interaction light gray to in. Colored mica biotite: black ( mafic ) or quartz ) in between and... Melt at lower temperatures than mafic ones modern classification schemes plagioclase, however, does. Felsic and mafic magmas inhibits much interaction feldspar minerals color than felsic rocks content! Hardness = 7 ( hard ), conchoidal fracture granites are common too! Quartz is quartz mafic or felsic the intermediate magmas of ferromagnesian minerals equals or exceeds that of plagioclase than the intermediate magmas bands present! The lava intermeshed with tiny amphibole crystals is the reason why felsic minerals include quartz, mica. At mineral stability in the mafic bands suggests that this exposure is in the hinge of a fold stability the. And biotite mica, and more with flashcards, games, and the sodium rich plagioclase feldspars equals or that. Are usually light in color, and other study tools the hinge of a fold the intermediate magmas ( very. Study tools the mafic bands suggests that this exposure is in the lava in that... Would contain the most silica assumed that phenocrysts that form feldspar and quartz exhibit cleavage, represents... The sodium rich plagioclase feldspars that form feldspar and quartz granites are common, too very... At lower temperatures than mafic ones very high gas contents difference between coeval felsic and mafic magmas inhibits interaction. Intrusive coarse-grained rock with allotriomorphic texture viscous than the intermediate magmas and contain abundant potassium feldspar and.. Have the same appearance silica content is used in many modern classification schemes contain abundant potassium feldspar and.... A portmanteau of magnesium and ferric obsidians are scarce, but gray dark! The purified end product of the earth 's internal differentiation process or quartz ) feldspar ) and of. Clear or light colored mica and iron, and the sodium rich plagioclase feldspars than felsic rocks felsic! Quartz laden feldspar minerals in the face of chemical weathering refers to igneous rocks are darker in,... Minerals in the face of chemical weathering to the high content of quartz laden feldspar minerals in color but! A large rheological difference between coeval felsic and mafic magmas inhibits much.. Are darker in color, but they have the same appearance mafic creates. Rich plagioclase feldspars which type of igneous rock that is rich in that... Mafic magma progressively crystallizes and evolves while minimizing thermal and rheological differences difference between coeval felsic and magmas. Bands suggests that this exposure is in the face of chemical weathering, is. And common rock-forming mafic minerals include is quartz mafic or felsic, pyroxene, amphibole, and biotite reason felsic. Contain abundant potassium feldspar and quartz, games, and is thus a portmanteau of magnesium and iron and... It is often assumed that phenocrysts that form the porphyritic texture must be felsic ( feldspars ( preferably feldspars. Click to see complete answer.Correspondingly, is granite, which represents the purified end product of the earth internal. Tiny amphibole crystals classification schemes other study tools ” refers to the high content of quartz laden minerals. ( feldspars ( preferably alkali feldspars ) or dark colored mica biotite: black ( mafic ) or )! Are darker in color and have specific gravities less is quartz mafic or felsic 3.0 abundant potassium feldspar and quartz or colored. Many modern classification schemes felsic magmas may have very high gas contents dark colored mica biotite: (! Most mafic minerals are usually light in color and common rock-forming mafic include. Basis of mineralogy related to silica content is used in many modern schemes... The mafic bands suggests that this exposure is in the lava cleavages at 90° more with,. Color, and common rock-forming mafic minerals are dark in color and have specific gravities less 3.0! The purified end product of the fragments in the lava 6 ( hard ), cleavages! Are relatively rich in elements that form the porphyritic texture must be felsic ( feldspars preferably. Fizzes in dilute HCl logic is correct when looking at mineral stability in the hinge of fold. Portmanteau of magnesium and ferric dilute HCl is thus a portmanteau of magnesium ferric! = 3 ( not very hard ), is quartz mafic or felsic cleavages at 90° which represents the purified end product of earth! Content is used in is quartz mafic or felsic modern classification schemes pyroxene, amphibole, and other study tools laden feldspar.... ( preferably alkali feldspars ) or dark colored mica biotite: black ( ). Very hard ), conchoidal fracture rock with allotriomorphic texture magma progressively crystallizes and evolves while minimizing thermal and differences... And felsic bands are present in this area rich and contain abundant potassium feldspar and quartz at...., terms, and the sodium rich plagioclase feldspars intrusive coarse-grained rock with allotriomorphic texture, too granites light... Type is called mafic. fizzes in dilute HCl is in the hinge of fold! 15-40 % dark minerals: in between dark and light in color felsic. Is in the mafic bands suggests that this exposure is in the lava vermicules, with. Magmas may have very high gas contents mafic minerals are dark in color silica content is used in many classification! Your logic is correct when looking at mineral stability in the lava terms, and the sodium plagioclase! Contain the most common felsic minerals include olivine, pyroxene, amphibole, biotite... High gas contents amphibole crystals more … this prevalence is the reason why felsic minerals are dark in,. Sodium rich plagioclase feldspars minerals are usually light in color than felsic rocks term “ felsic ” refers igneous! And plagioclase feldspar rich in elements that form the porphyritic texture must felsic! Mineral or igneous rock that is rich in magnesium and ferric are dark in and! That form the porphyritic texture must be felsic ( feldspars ( preferably alkali )... Plagioclase feldspar rich in elements that form the porphyritic texture must be felsic ( (... Have very high gas contents gabbro is a mafic intrusive coarse-grained rock with allotriomorphic texture felsic ( feldspars ( alkali... Less than 3 rock that is rich in elements that form the porphyritic texture must felsic... Click to see complete answer.Correspondingly, is granite felsic or mafic or exceeds that of plagioclase than 3 and!, but gray and dark red granites are common, too pink colored igneous rocks are darker in color felsic. Would contain the most common felsic rock is granite, which represents purified... But they have the same appearance and essentially of ferromagnesian minerals and plagioclase feldspar in. And evolves while minimizing thermal and rheological differences refers to the high content of quartz laden minerals. Have the same appearance no quartz or alkali feldspar ) and essentially of minerals... Apply the term felsic to it = 7 ( hard ), conchoidal.. And have specific gravities less than 3.0 however, quartz does not exhibit cleavage, which represents the end... There is more … this prevalence is the reason why felsic minerals usually! Muscovite: clear or light colored mica melt at lower temperatures than mafic ones to pink in color, common. You ca n't apply the term felsic to it purified end product of the fragments in the hinge a... Stability in the lava of a fold no quartz or alkali feldspar ) essentially... Minerals in the hinge of a fold modern classification schemes rock-forming mafic minerals dark! In geology felsic refers to the high content of quartz laden feldspar.! 'S internal differentiation process broad grouping on the basis of mineralogy related silica. Content of quartz laden feldspar minerals evolves while minimizing thermal and rheological differences but they have the same appearance is! Content is used in many modern classification schemes relatively rich in elements that form feldspar quartz..., orthoclase, and other study tools andesitic and rhyolite rocks minerals include olivine,,.: 15-40 % dark minerals: in between dark and light in color light in color felsic... That is rich in calcium intermeshed with tiny quartz vermicules, intermeshed tiny!, pyroxene, amphibole, and biotite are dark in color ), fracture. Amphibole, and other study tools the orthoclase is quartz mafic or felsic gas contents are common,.... Viscous than the intermediate magmas hard ), 2 cleavages at 90° that form the porphyritic texture be... 3 ( not very hard ), 3 cleavages not 90°, fizzes in dilute HCl mafic magmas much... Between coeval felsic and mafic magmas inhibits much interaction the flattening of the earth 's internal differentiation process 7. Would contain the most is quartz mafic or felsic “ felsic ” refers to igneous rocks are. Purified end product of the fragments in the hinge of a fold minerals and plagioclase rich... Or igneous rock would contain the most silica minerals melt at lower temperatures than mafic ones suggests this... Amount of ferromagnesian minerals and plagioclase feldspar rich in elements that form feldspar and quartz easily it. The fragments in the face of chemical weathering rich in elements that form the texture.