Anorthosite, type of intrusive igneous rock composed predominantly of calcium-rich plagioclase feldspar. All anorthosites found on Earth consist of coarse crystals, but some samples of the rock taken from the Moon are finely crystalline. Most anorthosites formed during Precambrian times.

2015-12-31 · Anorthosite with survey point, Split Rock State Park, MN. Image credit: Bill Mitchell . The name Corundum Point suggests the presence of corundum—a mineral used in abrasives—and it comes from a mining operation on the site in the early 1900s. However, the point is actually anorthosite, which was much less useful for abrasives.

Wenk H R, Joswig W, Tagai T, Korekawa M, Smith B K (1980) The average structure of An 62-66 labradorite American Mineralogist 65 81-95. 2010-03-05 Why Anorthosite consists of only one mineral and how the white-colored layers in many intrusions worldwide were created. Scientists at Wits University in Johannesburg say it is the decompression that causes plagioclase-saturation of rising magma. Some Magmas crystallize into rocks that consist of only one mineral.

Anorthosite minerals

When the amount of mafic minerals exceeds 10 % the name leucogabbro or anorthositic gabbro (alternatively -norite) is commonly used, depending on the nature of the pyroxene. Rock densities can provide valuable information on modes, especially where plagioclase and a mafic phase are the dominant minerals, as shown by Morse (1979a) for troctolites in the Kiglapait intrusion and by Cawthorn & Spies for pyroxenite to anorthosite packages in the Critical Zone of the Bushveld Complex. 2020-02-21 · Strictly speaking, the name “anorthosite” is applied to a rock composed of 90 to 100 of calcium-rich plagioclase feldspar and small amounts of high temperature minerals like pyroxene, olivine, magnetite (Fe3O4) or ilmenite (FeTiO3). The Majoqqap Qaava anorthosite deposit is located 125 km southeast of Greenland’s capital Nuuk on the southwest coast only 12 km from the ice-free coast of Qeqertarsuatsiaat Kangerdluat (Fiskenæs Fjord). The open pit mine will extract raw anorthosite, comprising the feldspar mineral Bytownite.

Cell Dimensions: a = 8.177, b = 12.877, c = 14.169, Z = 8; alpha = 93.166°, beta = 115.85°, gamma = 91.216° V = 1,340.29 Den (Calc)= 2.75.

Anorthite Crystallography. Axial Ratios: a:b:c =0.635:1:1.1003. Cell Dimensions: a = 8.177, b = 12.877, c = 14.169, Z = 8; alpha = 93.166°, beta = 115.85°, gamma = 91.216° V = 1,340.29 Den (Calc)= 2.75. Crystal System: Triclinic - Pinacoidal H-M Symbol ( 1) Space Group: P 1 ,I 1. X Ray Diffraction:

Scanning electron micrograph of anorthite. Anorthite in Thin Section Thin Section GigaPans. Anorthite in plane polars Anorthite in crossed polars.

About Anorthosite Hide A coarse-grained crystalline rock consisting mostly of calcic plagioclase (>90%, usually labradorite) with <10% mafics. The mafic mineral may be clinopyroxene, orthopyroxene, olivine, or, more rarely, amphibole. Oxides, mostly magnetite or ilmenite, are also common.

Norwegian anorthosite. Explore Jeannius Designs' photos on Flickr. Jeannius Designs has uploaded 3259 photos to Flickr. Minerals And Gemstones Crystals Minerals Today it is the majority shareholder of Greenland Anorthosite Resources which discovered a large anorthosite deposit on the country’s west coast. The mineral found there is particularly attractive given the rarity of its low-alkali content making it a more valuable, greener choice for use by fibreglass manufacturers and in aluminium production. Anorthosites occur as fragments or inclusions of widely varying size and shape in many other igneous rock types, ranging in composition from granite to basalt to kimberlite.

Extreme concentrations of these minerals give rise to minor ultramafic rocks, as well as the ilmenite-magnetite ore deposits 0003-004)v82t0r02-0014$02.00 14 Occurrences and Mineral Deposits. Strictly speaking, the name “anorthosite” is applied to a rock composed of 90 to 100 of calcium-rich plagioclase feldspar and small amounts of high temperature minerals like pyroxene, olivine, magnetite (Fe3O4) or ilmenite (FeTiO3). Feldspar is a very common mineral and occurs in virtually all igneous rocks 2019-06-04 Montana’s Moon-Like Rocks.
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Stillwater Anorthosite contains numerous sulfides contianing PGE's (Platinum Ground Elements) Stillwater Anorthosite Mineral # 710 another view Click on the mineral to enlarge the specimen, in the center and going down from there you can see what looks like pyrite.

The other end member, Anorthite, contains calcium and no sodium. The intermediary members are Oligoclase, Andesine, Labradorite, and Bytownite. Strictly speaking, the name “anorthosite” is applied to a rock composed of 90 to 100 of calcium-rich plagioclase feldspar and small amounts of high temperature minerals like pyroxene, olivine, magnetite (Fe3O4) or ilmenite (FeTiO3).
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Anorthosite, type of intrusive igneous rock composed predominantly of calcium-rich plagioclase feldspar. All anorthosites found on Earth consist of coarse crystals, but some samples of the rock taken from the Moon are finely crystalline. Most anorthosites formed during Precambrian times.

The Chugwater anorthosite generally … The Majoqqap Qaava anorthosite deposit is located 125 km southeast of Greenland’s capital Nuuk on the southwest coast only 12 km from the ice-free coast of Qeqertarsuatsiaat Kangerdluat (Fiskenæs Fjord). The open pit mine will extract raw anorthosite, comprising the feldspar mineral Bytownite. Anorthosite is by definition an igneous rock consisting of 90-100% plagioclase feldspar. When the amount of mafic minerals exceeds 10 % the name leucogabbro or anorthositic gabbro (alternatively -norite) is commonly used, depending on the nature of the pyroxene. 1972-01-28 2009-09-01 2010-03-05 all minerals gemstones by class etc.