Lunar Ferroan Anorthosite #60025 (Plagioclase Feldspar). Collected by Apollo 16 from the Lunar Highlands near Descartes Crater. This sample is currently on display at the National Museum of Natural History in Washington, DC.

Plagioclase is a very important series of tectosilicate minerals within the feldspar family. 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). The series ranges from albite to anorthite (with respective compositions NaAlSi₃O₈ to CaAl₂Si₂O₈), where sodium and calcium atoms can substitute for each other in the mineral's crystal lattice structure. Image File history File linksMetadata Download high resolution version (1200x1375, 270 KB) Summary Lunar Ferroan Anorthosite #60025 (Plagioclase Feldspar). ... Image File history File linksMetadata Download high resolution version (1200x1375, 270 KB) Summary Lunar Ferroan Anorthosite #60025 (Plagioclase Feldspar). ... Bulk composition of the Moons mantle and crust estimated, weight percent Oxygen 42. ... Anorthosite is a phaneritic, intrusive igneous rock characterized by a predominance of plagioclase feldspar (90-100%), and a minimal mafic component (0-10%). Pyroxene, ilmenite, magnetite, and olivine are the mafic minerals most commonly present. ... Feldspar is the name of an important group of rock-forming minerals which make up perhaps as much as 60% of the Earths crust. ... Apollo 16 was the tenth manned mission in the Apollo program and the fifth mission to land on the Moon. ... Exploring Shorty crater during the Apollo 17 mission to the Moon. ... Descartes is a heavily-worn lunar crater that is located in the rugged south-central highlands of the Moon To the southwest is the Abulfeda crater. ... The museum as seen from the National Mall, the Old Post Office Building visible in the distance National Mall museum entrance The National Museum of Natural History is a museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C. The museums collections total over... Aerial photo (looking NW) of the Washington Monument and the White House in Washington, DC. Washington, D.C., officially the District of Columbia (also known as D.C.; Washington; the Nations Capital; the District; and, historically, the Federal City) is the capital city and administrative district of the United... The silicate minerals make up the the largest and most important class of rock-forming minerals. ... Minerals are natural compounds formed through geological processes. ... Feldspar is the name of an important group of rock-forming minerals which make up perhaps as much as 60% of the Earths crust. ... A binary phase diagram displaying solid solutions over the full range of relative concentrations. ... Cleavage, in mineralogy, is the tendency of crystalline materials to split along definite planes, creating smooth surfaces, of which there are several named types: Basal cleavage: cleavage parallel to the base of a crystal, or to the plane of the lateral axes. ... Albite is an alkali feldspar mineral. ... Anorthite is one of the plagioclase feldspars, an important group of minerals abundant in the Earths crust. ... General Name, Symbol, Number sodium, Na, 11 Chemical series alkali metals Group, Period, Block 1, 3, s Appearance silvery white Atomic mass 22. ... General Name, Symbol, Number calcium, Ca, 20 Chemical series alkaline earth metals Group, Period, Block 2, 4, s Appearance silvery white Atomic mass 40. ... Properties For alternative meanings see atom (disambiguation). ... Crystallography (from the Greek words crystallon = cold drop / frozen drop, with its meaning extending to all solids with some degree of transparency, and graphein = write) is the experimental science of determining the arrangement of atoms in solids. ...

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. 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 extinction angle is an optical characteristic and varies with the albite fraction (%Ab). Earth cutaway from core to exosphere. ... Petrology is a field of geology which focuses on the study of rocks and the conditions by which they form. ... Volcanic rock on North America Plutonic rock on North America Igneous rocks are formed when molten rock (magma) cools and solidifies, with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. ... The refractive index (or index of refraction) of a material is the factor by which the phase velocity of electromagnetic radiation is slowed in that material, relative to its velocity in a vacuum. ... In optical mineralogy, a thin section is a laboratory preparation of a rock or mineral sample for use with a polarizing microscope. ... In electrodynamics, polarization (also spelled polarisation) is the property of electromagnetic waves, such as light, that describes the direction of their transverse electric field. ... A microscope (Greek: micron = small and scopos = aim) is an instrument for viewing objects that are too small to be seen by the naked or unaided eye. ...

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

Albite is named from the Latin albus, in reference to its unusually pure white color. 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. Albite is an alkali feldspar mineral. ... Oligoclase is a rock-forming mineral belonging to the plagioclase feldspars. ... Andesine is a feldspar mineral, a part of the plagioclase series. ... Labradorite, a feldspar mineral, is a member of the plagioclase series. ... Bytownite is a calcium rich member of the plagioclase solid solution series of feldspar minerals. ... Anorthite is one of the plagioclase feldspars, an important group of minerals abundant in the Earths crust. ... Commons:Imagem:Labradorite detail. ... Commons:Imagem:Labradorite detail. ... Latin is an ancient Indo-European language originally spoken in Latium, the region immediately surrounding Rome. ... This article or section does not cite its references or sources. ... A dike in geology refers to a tabular intrusive igneous body. ... The tourmaline mineral group is chemically one of the most complicated groups of silicate minerals. ... The mineral beryl is a beryllium aluminium cyclosilicate with the chemical formula Be3Al2(SiO3)6. ...

Anorthite was named by Rose in 1823 from the Greek meaning oblique, referring to its triclinic crystallization. Anorthite is characeristic of the mafic igneous rocks such as gabbro and basalt. 1823 was a common year starting on Wednesday (see link for calendar). ... In geology, mafic minerals and rocks are silicate minerals, magmas, and volcanic and intrusive igneous rocks that have relatively high concentrations of the heavier elements. ... Volcanic rock on North America Plutonic rock on North America Igneous rocks are formed when molten rock (magma) cools and solidifies, with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. ... Gabbro specimen. ... Basalt Basalt is a common gray to black volcanic rock. ...

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. It is a frequent associate of orthoclase. 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. Quarrying granite for the Mormon Temple, Utah Territory. ... Syenite 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 small amounts. ... Categories: Mineral stubs | Igneous rocks ... Gneiss Gneiss is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from preexisting formations that were originally either igneous or sedimentary rocks. ... Orthoclase (KAlSi3O8) is an important igneous rock forming tectosilicate mineral. ... Hematite (AE) or haematite (BE) 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, is the oxide of silicon, chemical formula SiO2. ... This article is about volcanoes in geology. ... A sample of andesite (dark groundmass) with amygdaloidal vesicules filled with zeolite. ...

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. Labradorite frequently shows an iridescent display of colors due to light refracting within the lamellae of the crystal. It is named after Labrador, where it is a constituent of the intrusive igneous rock anorthosite which is composed almost entirely of plagioclase. A variety of labradorite known as spectrolite is found in Finland. Figure 1:Mantle-peridotite xenolith with green peridot olivine and black pyroxene crystals from San Carlos Indian Reservation, Gila Co. ... For the logical fallacy, see Amphibology. ... The iridescence of the Blue Morpho butterfly wings. ... This article is about the region in Canada. ... Anorthosite is a phaneritic, intrusive igneous rock characterized by a predominance of plagioclase feldspar (90-100%), and a minimal mafic component (0-10%). Pyroxene, ilmenite, magnetite, and olivine are the mafic minerals most commonly present. ... Spectrolite is a hard and rare variety of labradorite feldspar. ...

Bytownite, named after the former name for Ottawa, Canada (Bytown), is a rare mineral occasionally found in more basic rocks. Motto: Advance Ottawa/Ottawa en avant Coordinates: Country Canada Province Ontario County Established 1850 as Bytown City Mayor Bob Chiarelli Governing body Ottawa City Council MPs / MPPs See list (includes Senators) Area    - City 2,778. ...

See also

• List of minerals

Gem animals. ...

References

• Alkali feldspar U. Texas
• Webmineral