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Northwest Africa 5230
Basic information Name: Northwest Africa 5230
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 5230
Observed fall: No
Year found: 2007
Country: (Northwest Africa)
Mass:help 909 g
Meteoritical Bulletin:  MB 96  (2009)  Polymict eucrite
Recommended:  Eucrite-pmict    [explanation]

This is 1 of 414 approved meteorites classified as Eucrite-pmict.   [show all]
Search for other: Achondrites, Eucrites, and HED achondrites
Comments: Approved 22 May 2009
Writeup from MB 96:

Northwest Africa 5230                                                                                

Northwest Africa

Find: October 2007

Achondrite (polymict eucrite)

History: Purchased by Space Jewels Switzerland in October 2007 from a Moroccan dealer in Switzerland.

Physical characteristics: A single stone (909 g) composed of abundant white to dark gray clasts (up to 5 mm), and less abundant limpid, pale bluish to colorless maskelynite crystals (up to 1.4 mm), in a finer grained, medium gray matrix.

Petrography (A. Irving and S. Kuehner, UWS): Polymict breccia composed of mineral fragments and lithic clasts in a finer matrix of the same phases.  Mineral fragments include compositionally variable low-Ca pyroxene (mostly unexsolved pigeonite and some orthopyroxene), completely maskelynitized calcic plagioclase, exsolved pigeonite (orthopyroxene with augite lamellae), unexsolved subcalcic ferriaugite (rimmed by fayalite), olivine, silica polymorph, chromite, ilmenite, Ni free metal, troilite and rare zircon.  Lithic clasts include both cumulate and basaltic eucrites, intergrowths of troilite+orthopyroxene+silica polymorph, and a rare mesosiderite clast (composed of ~50 vol.% metal with orthopyroxene, calcic plagioclase and chromite).

Geochemistry: Pigeonite (Fs31.1Wo11.0, FeO/MnO = 29.6), some with rims of ferroan low-Ca pyroxene (Fs55.9Wo3.1, FeO/MnO = 30.7); diogenitic low-Ca pyroxene (Fs26.2Wo3.5, FeO/MnO = 28.6); plagioclase (maskelynite, An76.5-95.1Or1.7-0.2).

Classification:  Achondrite (polymict eucrite).  This specimen is paired with NWA 4883, and contains distinctive large plagioclase grains completely transformed to maskelynite; the presence of clasts of mesosiderite is unusual among eucrites.  The sparseness of diogenitic debris makes this specimen a polymict eucrite breccia rather than a howardite.

Specimens: A total of 22.25 g of sample and one polished thin section are on deposit at UWS.  The main mass is held by Space Jewels Switzerland.

Data from:
  Table 2
  Line 28:
State/Prov/County:Northwest Africa
Mass (g):909.0
Class:Polymict eucrite
Ferrosilite (mol%):31.1
Wollastonite (mol%):11
Classifier:A. Irving, UWS
Type spec mass (g):22.25
Type spec location:UWS
Main mass:SJS
   and collections
UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012)
SJS: Space Jewels Switzerland, 2555 Brügg, Switzerland (private address; updated 3 Jan 2010)
References: Published in Meteoritical Bulletin, no. 96, MAPS 44, 1355-1397 (2009)
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Space Jewels   

     This is 1 of 9776 approved meteorites from (Northwest Africa) (plus 1862 unapproved names)

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