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Northwest Africa 12749
Basic information Name: Northwest Africa 12749
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12749
Observed fall: No
Year found: 2019
Country: (Northwest Africa)
Mass:help 497 g
Classification
  history:
Recommended:  Howardite    [explanation]

This is 1 of 374 approved meteorites classified as Howardite.   [show all]
Search for other: Achondrites, HED achondrites, and Howardites
Comments: Approved 26 Sep 2019
Writeuphelp
Writeup from MB 108:

Northwest Africa 12749 (NWA 12749)

(Northwest Africa)

Purchased: 2019

Classification: HED achondrite (Howardite)

History: Two stones weighing 497.29 g were found in Western Sahara prior to 2019. John Sinclair and J. Donald Cline purchased the samples from a meteorite dealer while at the 2019 Tucson Gem and Mineral Show.

Physical characteristics: The sample has a light orangish-brown exterior with a distinctive brecciated texture. The samples lack fusion crust. Dark brown to dark-greenish clasts up to 4 cm are visible on the exterior of the stone.

Petrography: Description and classification (A. Love, App): Sample is a breccia composed of rounded to angular dominant mineral and subordinate lithic fragments with an average diameter of 2.7 mm and some as large as 4 cm. Diogenite (~60 vol%) occurs primarily as zoned crystals and fragments of Opx, although a rare lithic fragment shows interlocking crystals that share 120º grain boundaries. Eucrites (~40 vol%) occur as basaltic and cumulate lithic fragments as well as individual twinned plagioclase and exsolved Cpx crystals. Other phases include pyroxene rimmed silica objects, FeNi metal, FeS, and chromite.

Geochemistry: (A. Love, App) Diogenite clasts: low Ca pyroxene Fs31.0±2.4Wo1.9±0.4 (Fs26.5-34.0Wo1.2-2.9), Fe/Mn=31.1±1.5, N=20. Eucrite clasts: low Ca pyroxene Fs34.8±3.4Wo2.1±0.4 (Fs28.0-41.5Wo1.5-2.7), Fe/Mn=29.7±4.9, Mg#57.5-71.4, n=18; high Ca pyroxene exsolution lamellae Fs15.8±1.4Wo42.1±0.7 (Fs13.0-17.6Wo41.4-43.6), Fe/Mn=23.0±3.9, N=10; plagioclase An92.5±2.0Or0.3±0.1, N=8.

Classification: HED (Howardite). Textures, FeO/MnO and Fs compositions of pyroxenes indicate this sample belongs to the HED meteorites. Sample is a howardite with a subequal mixture of eucrite and diogenite.

Specimens: PARI holds the main mass. One endcut weighing 21.59 g and a polished mount are on deposit at App.

Data from:
  MB108
  Table 0
  Line 0:
Place of purchase:Tucson Gem and Mineral Show
Date:P 2019
Mass (g):497.3
Pieces:2
Class:Howardite
Shock stage:low
Weathering grade:low
Ferrosilite (mol%):31.0±2.4; 34.8±3.4; 15.8±1.4
Wollastonite (mol%):1.9±0.4; 2.1±0.4; 42.1±0.7
Magnetic suscept.:3.31
Classifier:A. Love, App
Type spec mass (g):21.6
Type spec location:App
Main mass:PARI
Finder:Unknown
Comments:Submitted by Anthony Love
Institutions
   and collections
App: Department of Geology, 572 Rivers St., Appalachian State University, Boone, NC 28608, United States (institutional address; updated 7 Mar 2013)
PARI: Pisgah Astronomical Research Institute 1 Pari Dr Rosman, NC 28772, United States (institutional address; updated 13 Sep 2016)
Catalogs:
References: Published in Meteoritical Bulletin, no. 108, in preparation (2019)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 6968 approved meteorites from (Northwest Africa) (plus 2012 unapproved names)

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