anorthite


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Related to anorthite: labradorite

anorthite

(ănôr`thīt): see feldsparfeldspar
or felspar
, an abundant group of rock-forming minerals which constitute 60% of the earth's crust. Chemically the feldspars are silicates of aluminum, containing sodium, potassium, iron, calcium, or barium or combinations of these elements.
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anorthite

[ə′nȯr‚thīt]
(mineralogy)
The white, grayish, or reddish calcium-rich end member of the plagioclase feldspar series; composition ranges from Ab10 An90 to Ab0 An100, where Ab = NaAlSi3O8 and An = CaAl2Si2O8. Also known as calciclase; calcium feldspar.
References in periodicals archive ?
The appearance of calcium-rich plagioclases, like anorthite, can be considered appropriate to elaborate cooking pots.
It was found that in samples of tiles of basalt containing mass are present crystals of augite, quartz, anorthite and a small amount of hematite.
high-frequency of anorthite in basalt rocks and sintered basalt parts offers them an under--cooling state characterized by a total lack of elasticity;
Variation within any individual grain is as much as seven percent anorthite.
PHOTO : CL micrograph of a buildup sample showing anorthite (yellow), corundum (red) and hercynite (black) crystals.
Product Overview II-3 Feldspar: A Common Silicate II-3 General Chemical Formula II-3 Na-Feldspars are Widely Used II-3 Physical Properties II-4 Grades II-4 Glass Grade II-4 Ceramic Body Grade II-4 Glaze Grade II-4 Types II-5 Potassium Feldspar Group II-5 Plagioclase Feldspar Group II-5 Other Feldspars II-5 Rare Feldspars II-5 Characteristics of Major Feldspar Minerals II-6 Albite (moonstone) II-6 Oligoclase Feldspar II-6 Anorthite II-7 Microcline II-7 Orthoclase II-8 History II-8 Feldspars as Gemstones II-8 Principal Stones in Feldspar Group II-9 Labradorite II-9 Moonstone II-9 Sunstone II-9 Amazonite II-9 Orthoclase II-10 Occurrence II-10 Ores and Production Process II-10 Places of Origin II-10 Production II-11
The analysed compositions display a typically alkaline trend of increasing orthose with decreasing anorthite (Fig.
Fritz S J, Mohr DW (1984) Chemical alteration in the micro weathering environment within a spheroidally weathered anorthite boulder.
Standards and elements lines were as follows: magnesian manganoan fayalite (SiK[alpha], MgK[alpha], MnK[alpha], and FeK[alpha]), synthetic anorthite (AlK[alpha] and CaK[alpha]), rutile (TiK[alpha]), synthetic ZnO (ZnK[alpha]), Amelia albite (NaK[alpha]), and microcline (KK[alpha]).
Plagioclase is cloudy to saussuritized in some rocks especially in the more calcic cores but where fresh it is of intermediate anorthite content (calcic oligoclase to andesine).