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Northwest Africa 12998
Basic information Name: Northwest Africa 12998
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12998
Observed fall: No
Year found: 2017
Country: Northwest Africa
Mass:help 26 g
Classification
  history:
Recommended:  Winonaite    [explanation]

This is 1 of 38 approved meteorites classified as Winonaite.   [show all]
Search for other: Primitive achondrites, Winonaites
Comments: Approved 15 Dec 2019
Writeuphelp
Writeup from MB 108:

Northwest Africa 12998 (NWA 12998)

Northwest Africa

Purchased: 2017

Classification: Primitive achondrite (Winonaite)

History: Purchased by Matthew Stream from a meteorite dealer in 2017 at the Tucson Gem and Mineral Show.

Physical characteristics: Single stone with dark-brown fusion crust.

Petrography: (D. Sheikh, FSU) No chondrules present. 120° triple junctions present at mineral grain boundaries. Sample contains forsterite, enstatite, augite, troilite, Fe-Ni metal (~10-15 vol%, with grain size 100-30 µm), and Fe-oxides. Silicate grain size is 100-200 µm.

Geochemistry: Olivine (Fa0.7±0.2, FeO/MnO=7±1, n=25), Low-Ca Pyroxene (Fs3.2±0.2Wo1.4±0.1, FeO/MnO=8±1, n=22), High-Ca Pyroxene (Fs1.4±0.3Wo45.2±0.5, FeO/MnO=7±1, n=12).

Classification: Primitive achondrite (winonaite) based on the presence of near endmember forsterite and enstatite.

Specimens: 6.01 grams at UCLA; main mass with Matthew Stream.

Data from:
  MB108
  Table 0
  Line 0:
Place of purchase:Tucson, AZ
Date:P 2017
Mass (g):26
Pieces:1
Class:Winonaite
Shock stage:low
Weathering grade:moderate
Fayalite (mol%):0.7±0.2
Ferrosilite (mol%):3.2±0.2, 1.4±0.3
Wollastonite (mol%):1.4±0.1, 45.2±0.5
Classifier:D. Sheikh, FSU
Type spec mass (g):6.01
Type spec location:UCLA
Main mass:Matthew Stream
Comments:Submitted by Daniel Sheikh
Institutions
   and collections
UCLA: Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90095-1567, United States (institutional address; updated 17 Oct 2011)
FSU: Department of Geological Sciences, Florida State University, Tallahassee FL 32306-4100, United States (institutional address; updated 16 Dec 2010)
Catalogs:
References: Published in Meteoritical Bulletin, no. 108, in preparation (2019)
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Photos:
CreditPhotos
Public domain photographs:
Daniel Sheikh   
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 6 approved meteorites from Northwest Africa (plus 3 unapproved names)

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