Lunar Ferroan Anorthosite #60025 (Plagioclase Feldspar). Anorthosite (æˈnɔrθəsaɪt/ /ə- is a Phaneritic, Intrusive Igneous rock characterized by a predominance of Plagioclase Feldspar Feldspar is the name of a group of rock-forming Minerals which make up as much as 60% of the Earth 's crust. Collected by Apollo 16 from the Lunar Highlands near Descartes Crater. The geology of the Moon (sometimes called selenology, although the latter term can refer more generally to "lunar Descartes is a heavily-worn lunar crater that is located in the rugged south-central highlands of the Moon. This sample is currently on display at the National Museum of Natural History in Washington, DC, United States (unknown scale)

Plagioclase is a very important series of tectosilicate minerals within the feldspar family. The National Museum of Natural History is a Natural history Museum administered by the Smithsonian Institution, located on the National Washington DC ( formally the District of Columbia and commonly referred to as Washington, the District, or simply D The United States of America —commonly referred to as the The silicate minerals make up the largest and most important class of rock-forming Minerals They are classified based on the structure of their silicate Ion group A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific Feldspar is the name of a group of rock-forming Minerals which make up as much as 60% of the Earth 's crust. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a solid solution series, more properly known as the plagioclase feldspar series (from the Greek "oblique fracture", in reference to its two cleavage angles). A solid solution is a Solid - state Solution of one or more solutes in a Solvent. Cleavage, in Mineralogy, is the tendency of crystalline materials to split along definite planes creating smooth surfaces of which there are several named types The series ranges from albite to anorthite endmembers (with respective compositions NaAlSi₃O₈ to CaAl₂Si₂O₈), where sodium and calcium atoms can substitute for each other in the mineral's crystal lattice structure. Albite is a plagioclase Feldspar Mineral. It is the sodium endmember of the Plagioclase Solid solution series Anorthite is a compositional variety of Plagioclase Feldspar. An endmember in Mineralogy is a Mineral that is at the extreme end of a mineral series in terms of purity Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 History See also Atomic theory, Atomism The concept that matter is composed of discrete units and cannot be divided into arbitrarily tiny Crystallography is the experimental science of determining the arrangement of Atoms in Solids In older usage it is the scientific study of Crystals The Plagioclase in hand samples is often identified by its polysynthetic twinning or 'record-groove' effect.

Plagioclase is a major constituent mineral in the Earth's crust, and is consequently an important diagnostic tool in petrology for identifying the composition, origin and evolution of igneous rocks. In Geology, a crust is the outermost solid shell of a planet or moon In Geology, petrology (from Greek πέτρα petra, rock and λόγος logos, knowledge is the study of rocks and the conditions on which Igneous rocks (etymology from Latin ignis, fire are rocks formed by solidification of cooled Magma (molten rock Plagioclase is also a major constituent of rock in the highlands of the Earth's moon. The geology of the Moon (sometimes called selenology, although the latter term can refer more generally to "lunar

The composition of a plagioclase feldspar is typically denoted by its overall fraction of anorthite (%An) or albite (%Ab), and readily determined by measuring the plagioclase crystal's refractive index in crushed grain mounts, or its extinction angle in thin section under a polarizing microscope. The refractive index (or index of Refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves is reduced inside the medium In Optical mineralogy and Petrography, a thin section is a Laboratory preparation of a rock, Mineral or Soil sample for Polarization ( ''Brit'' polarisation) is a property of Waves that describes the orientation of their oscillations A microscope ( Greek: ( micron) = small + ( skopein) = to look or see is an instrument for viewing objects that are The extinction angle is an optical characteristic and varies with the albite fraction (%Ab). There are several named plagioclase feldspars that fall between albite and anorthite in the series. The following table shows their compositions in terms of constituent anorthite and albite percentages.

Labradorite displaying typical iridescent effect termed labradorescence(unknown scale)

A microphotograph of a plagioclase crystal under cross polarized light. Albite is a plagioclase Feldspar Mineral. It is the sodium endmember of the Plagioclase Solid solution series Oligoclase is a rock-forming Mineral belonging to the Plagioclase Feldspars In chemical composition and in its crystallographic and physical characters Andesine is a Feldspar Mineral, a part of the Plagioclase series Labradorite ((CaNa(AlSi4O8 a Feldspar Mineral, is an intermediate to calcic member of the Plagioclase series Bytownite is a calcium rich member of the Plagioclase Solid solution series of Feldspar Minerals It is usually defined as having "% Anorthite is a compositional variety of Plagioclase Feldspar. The plagioclase crystal shows a distinct banding effect called a Polysynthetic twinning. (unknown scale)

Albite is named from the Latin albus, in reference to its unusually pure white color. Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. It is a relatively common and important rock-making mineral associated with the more acid rock types and in pegmatite dikes, often with rarer minerals like tourmaline and beryl. Pegmatite is a very coarse-grained Igneous rock that has a grain size of 20 mm or more such rocks are referred to as pegmatitic. A dike or dyke in Geology is a type of Sheet intrusion referring to any geologic body that cuts Discordantly ' across planar Tourmaline is a Crystal Silicate mineral compounded with elements such as Aluminium, Iron, Magnesium, Sodium, Lithium The Mineral beryl is a Beryllium Aluminium cyclosilicate with the Chemical formula Be3Al2(SiO36

Anorthite was named by Rose in 1823 from the Greek meaning oblique, referring to its triclinic crystallization. Year 1823 ( MDCCCXXIII) was a Common year starting on Wednesday (link will display the full calendar of the Gregorian Calendar (or a Common Anorthite is a comparatively rare mineral but occurs in the basic plutonic rocks of some orogenic calc-alkaline suites. Orogeny (Greek for "mountain generating" is the process of natural Mountain building and may be studied as a tectonic structural event as a geographical event and Calc-alkaline and calc-alkalic are equivalent terms applied to groups of Igneous rocks that commonly occur together and that have compositions related by the characteristic

The intermediate members of the plagioclase group are very similar to each other and normally cannot be distinguished except by their optical properties.

Oligoclase is common in granite, syenite, diorite and gneiss. Granite (ˈɡrænɪt is a common and widely occurring type of intrusive, Felsic, igneous rock. Syenite is a coarse-grained intrusive Igneous rock of the same general composition as Granite but with the Quartz either absent or present in relatively Diorite (ˈdaɪəraɪt is a grey to dark grey intermediate intrusive Igneous rock composed principally of Plagioclase Feldspar (typically Gneiss (ˈnaɪs is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from preexisting formations that were originally It is a frequent associate of orthoclase. Physical properties Orthoclase crystallizes in the Monoclinic crystal system The name oligoclase is derived from the Greek for little and fracture, in reference to the fact that its cleavage angle differs significantly from 90°. Sunstone is mainly oligoclase (sometimes albite) with flakes of hematite. See also Nauvoo Temple for an article including information on the Latter-day Saint motif known as a Sunstone and Sunstone Magazine for the magazine of Hematite, also spelt hæmatite, is the Mineral form of Iron(III oxide (Fe2O3 one of several Iron oxides

Andesine is a characteristic mineral of rocks such as diorite which contain a moderate amount of silica and related volcanics such as andesite. The Chemical compound silicon dioxide, also known as silica or silox (from the Latin " Silex " is an Oxide Plate tectonics and hotspots Divergent plate boundaries At the For the extinct cephalopod genus see Andesites. Andesite (ˈændəsaɪt is an igneous, Volcanic rock, of intermediate

Labradorite is the characteristic feldspar of the more basic rock types such as diorite, gabbro, andesite or basalt and is usually associated with one of the pyroxenes or amphiboles. The pyroxenes are a group of important rock-forming Silicate minerals found in many Igneous and metamorphic rocks. Amphibole (pronounced amfi-bowl defines an important group of generally dark-colored rock-forming inosilicate Minerals composed of double chain SiO4 Labradorite frequently shows an iridescent display of colors due to light refracting within the lamellae of the crystal. Iridescence is an Optical phenomenon in which Hue changes with the angle from which a surface is viewed It is named after Labrador, where it is a constituent of the intrusive igneous rock anorthosite which is composed almost entirely of plagioclase. Modern Labrador Just like its island neighbour Newfoundland early settlement in Labrador was tied to the sea as demonstrated by the Montagnais, Innu and Anorthosite (æˈnɔrθəsaɪt/ /ə- is a Phaneritic, Intrusive Igneous rock characterized by a predominance of Plagioclase Feldspar A variety of labradorite known as spectrolite is found in Finland. Spectrolite is a hard and rare variety of Labradorite Feldspar. Finland, officially the Republic of Finland ( is a Nordic country situated in the Fennoscandian region of northern Europe.

Bytownite, named after the former name for Ottawa, Canada (Bytown), is a rare mineral occasionally found in more basic rocks. Ottawa (ˈɒtəwə or sometimes /ˈɒtəwɑː/ is the Capital of Canada and the country's fourth largest municipality. Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page

See also

• List of minerals

References

• Webmineral