How To Use Feldspar In A Sentence
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The main constituent phases of these rocks are plagioclase, hornblende, pyroxene, quartz and K-feldspar, and accessory phases include magnetite, sphene, zircon and apatite.
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The flake mica produced in the U.S. comes from several sources: the metamorphic rock called schist as a by-product of processing feldspar and kaolin resources, from placer deposits, and from pegmatites.
Mica
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Various potassium silicates -- leucite, feldspar, sericite, and glauconite -- and the potassium sulphate, alunite, have received attention and certain of them have been utilized to a small extent, but none of them are normally able to compete on the market.
The Economic Aspect of Geology
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The unit is an orange/red-weathered ignimbrite, which is generally massive and strongly feldsparphyric.
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From Pliocene time the shallow emplacement of intrusive bodies resulted in thermal metamorphism (forming, for example, biotite, cordierite, andalusite, K-feldspar and corundum in pelites) and hydrothermal activity.
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The mineral assemblage comprises quartz, K-feldspar, albitic plagioclase, white mica, apatite, tourmaline and garnet.
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The province is also endowed with other non-traditional minerals including nickel, feldspar, emerald, limestone, granite, amethyst, sodalite and syenite.
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Figure parts a-e with crossed nichols. (a) Micrographic groundmass surrounds feldspar phenocryst fragment. (b) Micrographic groundmass around clinopyroxene phenocryst.
Granophyre_photos.html
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So much for the western line; in the Portillo pass, proceeding eastward, we meet an immense mass of conglomerate, dipping to the west 45 deg, which rest on micaceous sandstone, etc., etc., upheaved and converted into quartz-rock penetrated by dykes from the very grand mass of protogine (large crystals of quartz, red feldspar, and occasional little chlorite).
More Letters of Charles Darwin — Volume 1
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The feldspar statue keeps intent, slit-eyed watch over a tomb.
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Petrological observations show excess feldspar in many basaltic lavas which is most easily explained by crystal settling.
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The 7-35 m thick tuff is massive, rhyodacitic, K-feldsparrich and contains abundant siliceous nodules; it is interpreted as an ignimbrite.
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Strain shadows around feldspar porphyroclasts contain recrystallized potassium feldspar, plagioclase and quartz.
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Feldspar compositions in the groundmass are slightly more Or-rich than the phenocrystic feldspar, which ranges from An10Or15Ab75 to about An1Or44Ab55.
Granophyre.html
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The mineral assemblage is quartz + plagioclase + K-feldspar + biotite + cordierite + andalusite fibrolite.
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The sample is composed of K-feldspar, plagioclase and quartz with accessory apatite, magnetite, titanite, zircon and secondary epidote.
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Glass-forming substances are usually silica, boric oxide, phosphorous pentoxide, or feldspars.
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When minerals such as quartz and feldspars have received a radiation dose and are then heated, they emit light.
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Their primary rocks were mainly graywacke, debris sandstone and few feldspar sandstone, ext.
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Electron microprobe element maps show the distribution and quantity of alkali feldspar in the fine-grained groundmass of the altered basalts.
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Montmorillonite is a swelling clay formed from the degradation of silicates such as feldspars, volcanic minerals, chlorite and illite, and is commonly found in alkaline soils today.
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The plagioclase feldspar weathers to produce a whitish gray rock, while the mafic minerals (olivine, augite and hypersthene) produce contrasting darker grains.
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All five rock samples are mineralogically simple, and comprise mainly muscovite, quartz and feldspar with accessory epidote and biotite.
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Its most abundant mineral is feldspar, which accounts for two-thirds of the Earth's crust.
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Radiating fringe of feldspar in groundmass is in optical continuity with phenocryst, from which it nucleated. (e) Quartz phenocryst is surrounded by feldspar groundmass.
Granophyre_photos.html
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A volatile-rich metasomatic phase produced late growth of poikilitic K-feldspars, layered pegmatites and aplite dikes and an explosive network of dykes emanating out of the top of the Nuptse-Everest leucogranite.
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They were, no doubt, pieces of that saussurite jade, or compact feldspar, which we brought home from the
Travels to the Equinoctial Regions of America
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The mineral is found as small pink to gray masses of microcrystals in quartz-feldspar pegmatites and veins in association with astrophyllite, riebeckite, and zircon.
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Glass-forming substances are usually silica, boric oxide, phosphorous pentoxide, or feldspars.
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Melters such as feldspar, whiting (or limestone) and talc are sufficient for the higher temperatures above 1200
2. Kilns
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At temperatures above about 660°C complete solid solution occurs between the two alkali feldspar end-members sanidine and high albite, but below this there is a break and two feldspars of different composition occur together.
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In this rock, you get the recrystallization and foliation of quartz, feldspars, micas, and amphiboles into alternating light - and dark-colored bands.
Metamorphic rock
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They consist mostly of quartz and feldspars, with a little mica or amphibole.
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It is a reddish brown sandstone formed by detrital quartz, plagioclase, feldspar and muscovite, with subordinate apatite, zircon and opaque minerals.
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Electron microprobe element maps show the distribution and quantity of alkali feldspar in the fine-grained groundmass of the altered basalts.
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They consist of talcose-schiste, bluish-grey limestone, talc in beds, serpentine, black marble similar to the oldest in the Alps, quartz, feldspar, and porphyries.
Rambles in the Islands of Corsica and Sardinia with Notices of their History, Antiquities, and Present Condition.
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Invisible traces of quartz, calcite, gypsum and feldspar, the dust of its resting place for more than two millennia, cling to the bronze.
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The mineral assemblage comprises quartz, K-feldspar, albitic plagioclase, white mica, apatite, tourmaline and garnet.
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The Main Channel conglomerate is made up of a variety of well-rounded felsite, granophyre, and quartz-feldspar porphyry pebbles, suggesting a geologically diverse source terrane.
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Electron microprobe element maps show the distribution and quantity of alkali feldspar in the fine-grained groundmass of the altered basalts.
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Larger crystals of feldspar and quartz dominate the host rock.
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When minerals such as quartz and feldspars have received a radiation dose and are then heated, they emit light.
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Namely temperature of potash feldspar decomposition and calcium are favorable forming feldspar.
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Canadian feldspar nepheline syenite is sometimes used to lower bisk firing temperatures.
European Lithographic | SciFi, Fantasy & Horror Collectibles
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Several methods of producing potash fertilizer using potassium feldspar were introduced in brief.
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Rocks of the suite are distinguished from unassigned leucogranite sheets of the same age by the absence or paucity of K-feldspar, and by their less silicic compositions relative to the leucogranites.
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During obduction, mantle-derived magmas most likely evolved to granitic compositions by assimilation of sediments and by fractional crystallization of amphibole, feldspar, titanite and allanite.
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They contain large amounts of the feldspar mineral.
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All monazite grains are located in the rock matrix, which consists of quartz, muscovite, biotite, epidote, chlorite, plagioclase, potassium feldspar and garnet with a granoblastic texture.
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In the vein's central vug, ferroaxinite overlies a selvage (fault gouge) of quartz, orthoclase, and microcline feldspar and is followed by fine-grained calcite.
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Zircon (variety cyrtolite) commonly forms curved tetragonal crystals that radiate from a base of biotite crystals and terminate in adjacent feldspar.
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Uluru is composed of steeply dipping, feldspar-rich sandstone arkose and has been exposed as a result of folding, faulting, the erosion of surrounding rock and infill.
Uluru-Kata Tjuta National Park, Australia
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Feldspars are added as orthoclase in order to reduce the devitrification of the glass.
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Quartz is associated most commonly with aegirine and potassium feldspar as well as zircon.
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The rounded conglomerate pebbles consist of siltstone, mudstone, wacke, granophyric igneous rocks, and various intermediate to felsic volcanic rocks, set in a matrix rich in quartz and feldspar grains.
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They have a mineralogical association of quartz, diopside, actinolite, plagioclase and K-feldspar.
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The feldspar is decomposed with the resulting formation of epidote, which is quite prominent.
The Long Labrador Trail
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Brittle deformation is preserved as the occurrence of fractures within quartz grains that have been healed by authigenic quartz and by cataclastic flow of fragmented feldspar grains.
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Of these, alkali feldspar, particularly orthoclase, is the most common.
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Because of the preponderance of the mineral anorthite (a calcium-rich variety of the mineral plagioclase feldspar) this rock type is called anorthosite.
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When the basis of the lavas of the Malpays changes from pitchstone to obsidian, its colour is paler, and is mixed with grey; in this case, the feldspar passes by imperceptible gradations from the common to the vitreous.
Travels to the Equinoctial Regions of America
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The term contemporary formation is here taken in the sense attached to it by geologists, in speaking of beds of quartz in clay-slate, granular limestone in mica-slate or feldspar in gneiss.
Travels to the Equinoctial Regions of America
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It is important to geology not to confound the modern currents of lava, the heaps of basalt, green-stone, and phonolite, dispersed over the primitive and secondary formations, with those porphyroid masses having bases of compact feldspar, * which perhaps have never been perfectly liquified, but which do not less belong to the domain of volcanoes.
Travels to the Equinoctial Regions of America
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Localized cataclastic deformation is common in both areas of outcrop, with millimetre-scale shatter seams containing comminuted material and rounded strained grains of quartz and feldspar.
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When the sandstone contains appreciable quantities of feldspar the rock is called arkose.
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The rocks (like all the hills in Konkodoo) are a coarse reddish granite, composed of red feldspar, white quartz, and black shorl; but it differs from any granite I have seen, in having round smooth pebbles, many of them as large as a cannon shot.
The Journal of a Mission to the Interior of Africa, in the Year 1805
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Two-feldspar thermometry fails to retrieve peak temperatures from these rocks owing to late stage unmixing reducing the albite content of orthoclase.
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Most beds are almost monomictic, comprising quartz-feldspar porphyry clasts, whereas some other beds are highly heterogeneous.
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Minerals such as feldspar, which are insoluble in water, will not give a positive test.
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The rock also comprises feldspar-rich bands aligned parallel to the main fabric.
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At some locations sericite completely pseudomorphs topaz and the feldspars.
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They consist of talcose-schiste, bluish-grey limestone, talc in beds, serpentine, black marble similar to the oldest in the Alps, quartz, feldspar, and porphyries.
Rambles in the Islands of Corsica and Sardinia with Notices of their History, Antiquities, and Present Condition.
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The reappearance of feldspar in the detritus probably indicates erosion of a less mature source area.
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In most rocks feldspar is in too small grains and is too intimately associated with other minerals to be of commercial importance; in only one type of rock, pegmatite, which is an igneous rock of extremely coarse and irregular texture, are the feldspar crystals sufficiently large and concentrated to be commercially available.
The Economic Aspect of Geology
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It is a siliciferous subsulphate of alumina and potash, a compact feldspar, with the addition of sulphuric acid completely formed in it.
Travels to the Equinoctial Regions of America
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Although each mound had substantial amounts of quartz and kaolinite, minerals that reflected differences in mound material included magnetite, gypsum, hornblende, hematite, goethite, and feldspars.
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The rock is cemented by a mixture of quartz overgrowths, K-rich feldspar, and an oxidized ferruginous clay now dominated by chlorite.
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The tonalite is gneissic, banded on a decimetre scale, and loaded with discrete mafic enclaves, metasedimentary xenoliths and garnet, feldspar and rutile xenocrysts, such that the body has a migmatitic appearance.
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It consists of quartz, K-feldspar, plagioclase, biotite and white mica, and in places displays a graphic texture.
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All four samples are medium-grained, and comprise variable proportions of hornblende, feldspar and quartz with accessory biotite and titanite.
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Extreme cases are found in mineral groups such as apatite, amphibole, pyroxene, feldspar, and tourmaline.
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`Outcroppings of quartz or feldspar - "'But it could be water, frozen pools of it shining in the sunlight!
ANTI-ICE
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The conglomerate was deposited in tributary stream channels, and the pebbles consist almost entirely of quartz-feldspar phenocrystic rhyolite.
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Sand, the proppant, primarily quartz and feldspar aka ground up rock, is the material that gets lodged in cracks that open up, and keep those cracks open when force and pressure are removed, allowing less resistance between underground hydrocarbons, to allow them to become newly liberated hydrocarbons, which we use to power a significant portion of our country.
Energy 101: Hydraulic Fracturing - Vladimir’s blog - RedState
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These granite dikes are composed almost totally of potassium feldspar and quartz.
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Various potassium silicates -- leucite, feldspar, sericite, and glauconite -- and the potassium sulphate, alunite, have received attention and certain of them have been utilized to a small extent, but none of them are normally able to compete on the market.
The Economic Aspect of Geology
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These domes are composed of pelitic schists and gneisses folded around a core of K-feldspar granite and granitic gneiss.
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These rocks are composed predominantly of the minerals plagioclase feldspar, amphibole, and pyroxene.
Igneous rock
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Various potassium silicates -- leucite, feldspar, sericite, and glauconite -- and the potassium sulphate, alunite, have received attention and certain of them have been utilized to a small extent, but none of them are normally able to compete on the market.
The Economic Aspect of Geology
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Basalt is a fine-grained igneous rock that is primarily composed of the iron- and magnesium-rich minerals pyroxene and olivine and calcium-rich plagioclase feldspar.
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A gray, fine-grained arkosic sandstone tablet bearing an inscription in ancient Hebrew from the First Temple Period contains a rich assemblage of particles accumulated in the covering patina that includes calcite, dolomite, quartz and feldspar grains, iron oxides, carbon ash particles, microorganisms, and gold globules (1†"4 μm in diameter).
BiblePlaces Blog
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Quartz, feldspar, and the clay minerals make up the bulk of that contribution.
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The fault places massive fractured greenstones over relatively undeformed feldspar andesite porphyry.
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The minerals anorthite, albite, and orthoclase named in this figure are all feldspars; sylvite and halite are chlorides of potash and soda.
The Economic Aspect of Geology
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Various potassium silicates -- leucite, feldspar, sericite, and glauconite -- and the potassium sulphate, alunite, have received attention and certain of them have been utilized to a small extent, but none of them are normally able to compete on the market.
The Economic Aspect of Geology
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The clay slip is then screened through 60 or 100 mesh, other screened materials like talc or feldspar are added, the slip is thoroughly stirred, and in order to ensure a uniform mixing the slip is screened again. blunging: Where electric power is available, a high speed blunger is used.
Chapter 7
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In practice many basalts also contain easily visible crystals of feldspar, pyroxene, olivine, or amphibole.
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The rock here is a porphyritic granite (porhyritic meaning that the stone has large-grained crystals, such as feldspar or quartz, dispersed in a fine-grained feldspathic matrix or groundmass).
Of Books and the Sea
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The semi-pelites usually consist of biotite, quartz, plagioclase and untwinncd feldspar, and garnet forms abundant porphyroblasts in some varieties.
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The ore - hunting indicator is of calcite - potassium feldspar veins containing pyritohedron pyrite.
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Feldspar is dominated by microcline, but plagioclase and perthitic feldspar are also present.
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There is also added some more fusible substance, such as feldspar, gypsum, or lime, together with some pure quartz.
An Elementary Study of Chemistry
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The main constituent phases of these rocks are plagioclase, hornblende, pyroxene, quartz and K-feldspar, and accessory phases include magnetite, sphene, zircon and apatite.
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The center focal is an Oval shaped piece of Graphic Feldspar with a beautiful design occurring naturally in the piece.
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The white chalkstone glitters from afar; the light grey feldspar assumes a warm flesh tint; the limestone becomes straw color; the crystals of hornblende flash like fire-flies; and the veins of white quartz, running with their nodules of serpentine and chlorite through the dark clay-slate, gleam as do chain lightnings through the clouds.
Life of Schamyl And Narrative of the Circassian War of Independence Against Russia
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During obduction, mantle-derived magmas most likely evolved to granitic compositions by assimilation of sediments and by fractional crystallization of amphibole, feldspar, titanite and allanite.
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`Outcroppings of quartz or feldspar - "'But it could be water, frozen pools of it shining in the sunlight!
ANTI-ICE
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For example, the igneous rock called basalt was created at a great depth and contains little feldspar compared to granite, which formed near the surface.
6. Obtaining glaze materials
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Quartz is associated most commonly with aegirine and potassium feldspar as well as zircon.
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Although each mound had substantial amounts of quartz and kaolinite, minerals that reflected differences in mound material included magnetite, gypsum, hornblende, hematite, goethite, and feldspars.
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All monazite grains are located in the rock matrix, which consists of quartz, muscovite, biotite, epidote, chlorite, plagioclase, potassium feldspar and garnet with a granoblastic texture.
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I saw distinctly that, wherever they crossed each other, the veins containing mica and black schorl traversed and drove out of their direction those which contained only white quartz and feldspar.
Travels to the Equinoctial Regions of America
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Notwithstanding the great number of blocks, which we stopped to break, to the great regret of our guides, we could discover neither nepheline, leucite, * nor feldspar.
Travels to the Equinoctial Regions of America
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A dark red, finely laminated rock consisting chiefly of decomposed biotite and feldspar, occasional quartz grains and sericite and much iron oxide.
The Long Labrador Trail
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These granite dikes are composed almost totally of potassium feldspar and quartz.
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Over 150 minerals: mica, feldspar, beryl, amethyst, rose / smokey quartz, garnet, and Uranium minerals (gummite, autunite) prized by collectors / museums.
Undefined
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Sericite is fine-grained muscovite formed by alteration of such minerals as feldspar, cordierite, and sillimanite.
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All three are dominated by unaltered muscovite, quartz, K-feldspar and albite, with minor epidote.
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The general character of the rock here is sienitic; but, besides this peculiar quality of feldspar, the hornblende appears as actinolite, (ray-stone,) so called from the form of its crystallization; while the quartz element is faintly present, or appears in separate masses.
The Atlantic Monthly, Volume 15, No. 87, January, 1865
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It is home to glasses, pyroxenes, feldspars, oxides, olivines, troilite and metals in its lunar soil, which is called regolith.
Weekend SkyWatcher's Forecast: March 19-21, 2010 | Universe Today
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The name feldspar is a contraction of the longer name fieldspar, as some early specimens were found in fields.
Feldspar
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First, albite is the sodic feldspar that separates from a ‘host’ potassic feldspar to form perthite.
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The feldspar gems, such as moonstone, amazonite, and labradorite, also cleave very smoothly in certain directions.
A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public
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Figure parts a-e with crossed nichols. (a) Micrographic groundmass surrounds feldspar phenocryst fragment. (b) Micrographic groundmass around clinopyroxene phenocryst.
Granophyre_photos.html
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A large pebble with a gneissose appearance is a retrograded orthogneiss, consisting of quartz, plagioclase, feldspar and muscovite, with relics of biotite, mostly chloritized, and a weakly folded tectonic foliation.
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Perhaps 75\% of this is the plagioclase feldspars (mostly albite, oligoclase and labradorite) with the remainder as potassium feldspars (mostly microcline and orthoclase).
Netvouz - new bookmarks
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In 1977 and 1978 about 5,000 short tons of potassium feldspar were mined from the Blue Spar.
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Additional flux can be feldspar (preferably nepheline syenite), lime - stone, dolomite, frit or glass powder.
Chapter 9
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There are excellent, beautifully illustrated sections on the feldspars, quartz, topaz, and beryl.
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We began with the ‘Famous Four’ of petrified wood, labradorite, graphic feldspar and ocean jasper, and continued from there.
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This regular disposition of lithoid basaltic lava and feldsparry vitreous lava is analogous to the phenomena of all trappean mountains; it reminds us of those phonolites lying in very ancient basalts, those close mixtures of augite and feldspar which cover the hills of wacke or porous amygdaloids: but why are the porphyritic or feldsparry lavas of the Peak found only on the summit of the volcano?
Travels to the Equinoctial Regions of America
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`Need to get all the feldspar out of her hair," I told her, `and the mica.
THE WIDOW'S TRIAL
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Another advantage is that the higher firing temperature makes it possible to rely on non-fritted fluxes, like feldspar and limestone, for the glaze.
Chapter 9
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The main constituent phases of these rocks are plagioclase, hornblende, pyroxene, quartz and K-feldspar, and accessory phases include magnetite, sphene, zircon and apatite.
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All four samples are medium-grained, and comprise variable proportions of hornblende, feldspar and quartz with accessory biotite and titanite.
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They have a mineralogical association of quartz, diopside, actinolite, plagioclase and K-feldspar.
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In agreement with published literature, amphibole and pyroxene appeared to dissolve ahead of feldspar.
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Closer to the contact microcline is replaced by sanidine, and perthitic exsolution in detrital alkali feldspar begins to disappear.
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The siltstones contain poorly sorted angular fragments of quartz, and angular clasts and cleavage fragments of plagioclase and alkali feldspar.
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In samples consisting mainly of feldspars, clinopyroxene, garnet or amphibole occur as sub - to anhedral grains and grain sixes become smaller.
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The Bakfjord Granite contains quartz, K-feldspar, biotite, plagioclase, epidote, allanite, muscovite and occasional garnet.
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They make stoneware, porcelain and ‘raku’ at the pottery, using simple ingredients such as Dorset clay ball, Devon china clay, local sand, granite from Cornwall, feldspars, limestone and basalt from Somerset.
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A plagioclase feldspar, albite probably, occurs as parallel growths of transparent colorless to yellowish crystals.
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Other variants include feldspar-pyroxene-phyric lava and, rarely, aphyric lava.
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The coarse-grained sandstone matrix is dominated by feldspathic litharenites with 50-70% quartz, 2-5% K-feldspar and 10-15% plagioclase.
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Quartz, feldspar, white mica and biotite are all major constituents.
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Shimmering with dazzling soft lavender, violet or lilac luster to a deeper dark and mysterious purple with whirling patterns of black Augite, microcline feldspar lucid crystals tinged with orange Tinaksite describes the rare and recently discovered mineral gem Charoite.
SciFi, Fantasy & Horror Collectibles - Part 649
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The rock here is a porphyritic granite (porhyritic meaning that the stone has large-grained crystals, such as feldspar or quartz, dispersed in a fine-grained feldspathic matrix or groundmass).
Of Books and the Sea
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Of course plagioclase feldspars are also one of my favorites so I might be a little partial here.
5 Minerals
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The country granite typically has about 1/8 to 1/4 inch sized anhedral crystals of feldspar and quartz.
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The rock consists of plagioclase, K-feldspar, quartz, clinopyroxene and biotite, with abundant apatite, and ilmenite.
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A pomegranate is not a species of granular crystalline rock consisting essentially of quartz, orthoclase-feldspar, and mica, as I spelled it.
There's no "I" in inspiration... wait, what?
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These microfaults are commonly pulled apart with growth of new quartz and biotite between pulled apart feldspar and hornblende.
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Aligned igneous minerals of euhedral potassium feldspar, plagioclase, biotite and hornblende in an undeformed quartz matrix define a magmatic foliation.
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This regular disposition of lithoid basaltic lava and feldsparry vitreous lava is analogous to the phenomena of all trappean mountains; it reminds us of those phonolites lying in very ancient basalts, those close mixtures of augite and feldspar which cover the hills of wacke or porous amygdaloids: but why are the porphyritic or feldsparry lavas of the Peak found only on the summit of the volcano?
Travels to the Equinoctial Regions of America
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Feldspar has been hydrothermally altered by a fluorine-rich water vapor to quartz, mica (usually lithian), topaz and/or tourmaline with fluorite, cassiterite, molybdenite, rutile, and wolframite as typical accessory minerals.
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Like P133, it consists mainly of quartz, feldspar and white mica; plagioclase can also be distinguished under the microscope.
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Quartz, feldspar, and the clay minerals make up the bulk of that contribution.
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The minerals included in this group are orthoclase, microcline, and the plagioclase feldspars.
Feldspar
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The fine-grained matrix consists mainly of quartz and feldspar.
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They consist of talcose-schiste, bluish-grey limestone, talc in beds, serpentine, black marble similar to the oldest in the Alps, quartz, feldspar, and porphyries.
Rambles in the Islands of Corsica and Sardinia with Notices of their History, Antiquities, and Present Condition.
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The nature of the phonolites, which are lithoid lavas with a feldspar basis, and the nature of the green slates intermixed with hornblende, oppose this opinion.
Travels to the Equinoctial Regions of America
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Autunite is widespread in the eastern United States and is particularly well known as an accessory in complex pegmatites that have been prospected for mica, feldspar, spodumene, and gems.
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The sides of the crater present numerous loose masses, which appear to have been ejected, and consist of glassy feldspar, ice-spar, sodalite, hauyne, spinellane, and leucite.
COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1
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But genuine porcelain is made from a mixture of quite different materials -- a mixture of decomposed feldspar known as kaolin, and petuntse.
The Story of Porcelain
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Canadian feldspar nepheline syenite is sometimes used to lower bisk firing temperatures.
European Lithographic | SciFi, Fantasy & Horror Collectibles
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They were, no doubt, pieces of that saussurite jade, or compact feldspar, which we brought home from the Orinoco, and which La
Personal Narrative of Travels to the Equinoctial Regions of America, During the Year 1799-1804 — Volume 3
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A frit is a combination of a flux or several fluxes (lead, borax, boric acid, potassium carbonate) that is combined with other insoluble materials (quartz, feldspar, lime etc.), melted in a kiln to form an insoluble glass, and ground to be used as the base for making glazes.
7. Frits and fritmaking
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The skarn layer has a massive texture with two assemblages, wollastonite + quartz + diopside and prehnite + datolite + actinolite + K - feldspar, which have been interpreted as evidence of hydrothermal metasomatism of carbonate rocks.
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In addition to quartz, fluid inclusions can occur in carbonates, gypsum, halite, fluorite, feldspar, garnet, pyroxene, amphibole, tourmaline, olivine, and sphalerite; indeed in most minerals except phyllosilicates.
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The substance which I obtained from the hands of the Indians, belongs to the saussurite, * to the real jade, which resembles compact feldspar, and which forms one of the constituent parts of the verde de Corsica, or gabbro.
Travels to the Equinoctial Regions of America
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Simple inspection will show that granite rock, for example, is a mixture of three minerals, called feldspar, mica, and quartz.
Religion and Chemistry
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It is important to note that potassium feldspar did not deform in a ductile fashion during post-peak-metamorphic deformation.
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All of these rock types are light in color because of the dominance of quartz, potassium and sodium feldspars, and plagioclase feldspar minerals (Figure 1).
Igneous rock
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The first phase of diagenetic albite constitutes an impure, turbid variety including albitized grains of original plagioclase and alkali feldspar.
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As will be shown in the mineralogy section of this paper, the spilitic rocks are characterised by fresh augite, albitic feldspar, and an abundant development of epidote and pumpellyite.
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Plagioclase dramatically removes Sr at intermediate stages and alkali feldspars sequester Ba and Rb as late-stage trachytes and phonolites form in alkaline magmas.
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The groundmass of these leucocratic segregations is heterogeneous, consisting of centimeter-scale regions dominated by nepheline, natrolite, alkali feldspar, or wollastonite.
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The granite's granophyric groundmass consists of intergrown quartz and potassium feldspar (~Or45), the latter consisting of plumose splays that nucleated directly from pre-existing phenocrysts.
Granophyre.html
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The minerals included in this group are orthoclase, microcline, and the plagioclase feldspars.
Feldspar
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The rock here is a porphyritic granite (porhyritic meaning that the stone has large-grained crystals, such as feldspar or quartz, dispersed in a fine-grained feldspathic matrix or groundmass).
Of Books and the Sea
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Feldspar (including sanidine and plagioclase) separates were handpicked from a 62-125 mm sieve fraction crushed from megacrysts.
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There are no secondary sodic phases present, and no observed albitization of potassium feldspar, suggesting only limited Na mobility.
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In other cases, quartz is the predominant material, and in still other cases, where the best kaolin is produced, the proportion of both quartz and mica are small, and the feldspar is the prevailing material.
North Carolina and its Resources.
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The siltstones contain poorly sorted angular fragments of quartz, and angular clasts and cleavage fragments of plagioclase and alkali feldspar.
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The conversion of feldspar to cristobalite involves the removal of water.
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In some cases the secondary pore space created by feldspar dissolution may be infilled by clay reaction products, or the secondary pore space may be a net contribution to total rock porosity.
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Because of the preponderance of the mineral anorthite (a calcium-rich variety of the mineral plagioclase feldspar) this rock type is called anorthosite.
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The severe crushing to which the rock has been subjected has resulted in the conversion of the plagioclase into scapolite and also in the formation of zoisite by the characteristic alteration of the lime bearing silicate of the feldspar in conjunction with other constituents of the rock.
The Long Labrador Trail
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Along the vein wall, adjacent to the country rock, are fine-grained quartz, feldspar, and chlorite.
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In the vein's central vug, ferroaxinite overlies a selvage (fault gouge) of quartz, orthoclase, and microcline feldspar and is followed by fine-grained calcite.
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In some places the sulphur had formed crystals among other substances, such as whitish cinders made of an infinity of little feldspar crystals.
The Mysterious Island
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The central potassic zone is characterized by the presence of potassium-bearing minerals such as orthoclase (a potassium feldspar) and biotite.
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Quartz, feldspar, and the clay minerals make up the bulk of that contribution.
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High temperature (1100-1300°C) - primary flux: feldspar, nepheline syenite, fusible clay, wood ash.
12. Developing glazes
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(Feldspar) plagioclase, alkali-feldspar (H 6-6. 5)
Volcanic ash hazards and ways to minimize them
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The province is also endowed with other non-traditional minerals including nickel, feldspar, emerald, limestone, granite, amethyst, sodalite and syenite.
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Furthermore, the lunar orbiters confirmed that the highlands of the moon are dominated by anorthosite, an igneous rock composed primarily of the mineral feldspar and rich in calcium and aluminum.
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Graphic granite is a regular intergrowth of quartz and feldspar that gives an angular appearance suggestive of cuneiform writing (whence "graphic," which means "writing").
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Coarse granite (known as pegmatite) often breaks up in weathering, leaving large pieces of quartz and feldspar lying on the ground.
6. Obtaining glaze materials
