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Northwest Africa 13476
Basic information Name: Northwest Africa 13476
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13476
Observed fall: No
Year found: 2020
Country: (Northwest Africa)
Mass:help 251 g
Recommended:  Ureilite    [explanation]

This is 1 of 605 approved meteorites classified as Ureilite.   [show all]
Search for other: Achondrites, Ureilites
Comments: Approved 12 Dec 2020
Writeup from MB 109:

Northwest Africa 13476 (NWA 13476)

(Northwest Africa)

Purchased: 2020 Aug

Classification: Ureilite

History: Purchased by John Divelbiss in August 2020 from Matthew Stream, who acquired it from a Moroccan dealer.

Petrography: (A. Irving, UWS and P. Carpenter, WUSL) Protogranular aggregate of olivine (~70 vol.%) and low-Ca pyroxene (~30 vol.%). Olivine exhibits reduced, more magnesian rims associated with very fine grained Fe metal (some containing small granules of schreibersite). Accessory phases identified include graphite, troilite and Cr-troilite. The presence of microdiamond is also inferred from the extreme difficulty in cutting this specimen (the owner reported that several diamond saw blades were severely damaged in attempts to remove the type material).

Geochemistry: Olivine (cores Fa18.5±0.1, N = 4; rims Fa3.1-5.7, N = 4), low-Ca pyroxene (Fs16.1±0.1Wo4.8±0.1, N = 5; Fs9.2Wo6.2).

Classification: Ureilite.

Specimens: 22.4 g including one polished thin section at UWB; remainder with Mr. J. Divelbiss.

Data from:
  Table 0
  Line 0:
Place of purchase:Riverside, CA
Date:P 2020 Aug
Mass (g):251
Shock stage:high
Weathering grade:low
Fayalite (mol%):18.5±0.2
Ferrosilite (mol%):16.1±0.1
Wollastonite (mol%):4.8±0.1
Classifier:A. Irving, UWS, and P. Carpenter, WUSL
Type spec mass (g):22.4
Type spec location:UWB
Main mass:J. Divelbiss
Comments:JD20-6; submitted by A. Irving
   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)
WUSL: Washington Univ., One Brookings Drive, St. Louis, MO 63130, United States (institutional address; updated 17 Oct 2011)
UWB: University of Washington, Box 353010 Seattle, WA 98195, United States (institutional address; updated 27 Jul 2012)
References: Published in Meteoritical Bulletin, no. 109, in preparation (2020)
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     This is 1 of 8495 approved meteorites from (Northwest Africa) (plus 1899 unapproved names)

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