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Northwest Africa 12775
Basic information Name: Northwest Africa 12775
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12775
Observed fall: No
Year found: 2011
Country: (Northwest Africa)
Mass:help 51.5 g
Meteoritical Bulletin:  MB 108  (2020)  Eucrite
Recommended:  Eucrite    [explanation]

This is 1 of 569 approved meteorites (plus 1 unapproved name) classified as Eucrite.   [show all]
Search for other: Achondrites, Eucrites, and HED achondrites
Comments: Approved 11 Oct 2019
Writeup from MB 108:

Northwest Africa 12775 (NWA 12775)

(Northwest Africa)

Purchased: 2011

Classification: HED achondrite (Eucrite)

History: Cataloged in the ROM collection as LM55993.

Physical characteristics: The meteorite has a well-preserved, dark fusion crust, with no evident weathering. Interior of the meteorite intact, uniform and pale gray, with visible thin, black veins and very-fine grained texture.

Petrography: Fine-grained basalt, with equilibrated texture, slightly brecciated. A small vein that appears to be of impact origin. The sample contains a small clast that shows thermal disequilibration. Very fine grained plagioclase and pyroxene in the matrix, with seldom large laths of plagioclase and subordinate large pyroxene grains. Matrix plagioclase needle-shaped.

Geochemistry: Mineral composition and geochemistry: Plagioclase, An89.5±2.2 (n=18). Low-Ca pyroxene composition: Fs42.7±1.6Wo4.6±1.9 and Mg# 34.5-36.7 (n=8); high-Ca pyroxene composition: Fs24.1±8.6Wo38.1±15.3, Mg# 38.2-52.2 (n=10)

Classification: (A. Cernok, ROM) Sample is an equilibrated basaltic eucrite. Texture and compositions suggest the sample has experienced thermal equilibration.

Data from:
  Table 0
  Line 0:
Place of purchase:Tucson Gem and Mineral Show
Date:P 2011
Mass (g):51.53
Shock stage:low
Weathering grade:low
Ferrosilite (mol%):42.7±1.6, 24.1± 8.6.
Wollastonite (mol%):4.6±1.9, 38.1±15.3
Classifier:A. Cernok, ROM
Type spec mass (g):10.31
Type spec location:ROM
Main mass:DGregory
Comments:Submitted by V. Di Cecco, ROM
   and collections
ROM: Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario M5S 2C6, Canada (institutional address; updated 18 Oct 2011)
DGregory: David Gregory, 230 First Avenue, Suite 108, St. Thomas, Ontario N5R 4P5, Canada (private address)
References: Published in Meteoritical Bulletin, no. 108 (2020) Meteorit. Planet. Sci. 55, 1146-1150
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     This is 1 of 8904 approved meteorites from (Northwest Africa) (plus 1871 unapproved names)

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