Pargasite

Pargasite

Infobox mineral
name = Pargasite
category = Silicate mineral
boxwidth =
boxbgcolor =


caption =
formula = NaCa2(Mg,Fe++)4Al(Si6Al2)O22(OH)2
molweight =
color = Bluish green, grayish black, light brown
habit = Stout prismatic to tabular
system = Monoclinic; 2/m
twinning = Simple and lamellar - common
cleavage = {110} perfect
fracture = Splintery
mohs = 5 - 6
luster = Vitreous
refractive = nα = 1.630 nβ = 1.640 nγ = 1.650
opticalprop = Biaxial (-)
birefringence = δ = 0.020 max.
pleochroism =
streak =
gravity = 3.04 - 3.17
density =
melt =
fusibility =
diagnostic =
solubility =
diaphaneity = Translucent, will transmit light on thin edges.
other =
references = http://www.handbookofmineralogy.org/pdfs/pargasite.pdf Handbook of Mineralogy] http://www.mindat.org/min-3119.html Mindat] http://webmineral.com/data/Pargasite.shtml Webmineral]

Pargasite is a complex inosilicate mineral with formula NaCa2(Mg,Fe++)4Al(Si6Al2)O22(OH)2.

It was first described for an occurrence in Pargas, Finland in 1814 and named for the locality.

It occurs in high temperature regional metamorphic rocks and in the skarns within contact aureoles around igneous intrusions. It also occurs in andesite volcanic rocks and altered ultramafic rocks.

Referenses


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  • pargasite — ● pargasite nom féminin (de Pargas, nom propre) Variété d amphibole calcique, monoclinique. ⇒PARGASITE, subst. fém. MINÉR. Espèce minéralogique de couleur bleu foncé, vert olive, vert noirâtre ou céladon, variété de hornblende. La pargasite, du… …   Encyclopédie Universelle

  • Pargasite — Par gas*ite, n. [So called from Pargas, in Finland.] (Min.) A dark green aluminous variety of amphibole, or hornblende. [1913 Webster] …   The Collaborative International Dictionary of English

  • pargasite — /pahr geuh suyt /, n. Mineral. a green or bluegreen variety of hornblende. [1810 20; named after Pargas, town in Finland; see ITE1] * * * …   Universalium

  • pargasite — (par ga zi t ) s. f. Terme de minéralogie. Silicate de magnésie, de chaux et d alumine. ÉTYMOLOGIE    Pargas, île de la côte de Finlande …   Dictionnaire de la Langue Française d'Émile Littré

  • pargasite — par·gas·ite …   English syllables

  • pargasite — /ˈpagəsaɪt/ (say pahguhsuyt) noun a variety of hornblende, containing fluorine, sodium, and aluminium. {named after Pargas, town in Finland} …  

  • pargasite — ˈpärgəˌsīt noun ( s) Etymology: German pargasit, from Pargas, town in Finland + German it ite : a green or bluish green hornblende containing sodium …   Useful english dictionary

  • Amphibole — (pronounced amfi bowl) defines an important group of generally dark colored rock forming inosilicate minerals, composed of double chain SiO4 tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their… …   Wikipedia

  • Blueschist — (pronEng|ˈbluːʃɪst) is a rock that forms by the metamorphism of basalt and rocks with similar composition at high pressures and low temperatures, approximately corresponding to a depth of 15 to 30 kilometers and 200 to 500 degrees Celsius. The… …   Wikipedia

  • Lamprophyre — Lamprophyres (Greek λαµπρός (lamprós) = bright and φύρω (phýro) = to mix) are uncommon, small volume ultrapotassic igneous rocks primarily occurring as dikes, lopoliths, laccoliths, stocks and small intrusions. They are alkaline silica… …   Wikipedia

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