Meteoritical Bulletin: Entry for Northwest Africa 12998

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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: 26 g

Classification
history:

Meteoritical Bulletin:	MB 108	(2020)	Winonaite
Recommended:			Winonaite [explanation]

This is 1 of 80 approved meteorites (plus 1 unapproved name) classified as Winonaite. [show all]
Search for other: Primitive achondrites, Winonaites

Comments:

Approved 15 Dec 2019

Writeup

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 (Fa_0.7±0.2, FeO/MnO=7±1, n=25), Low-Ca Pyroxene (Fs_3.2±0.2Wo_1.4±0.1, FeO/MnO=8±1, n=22), High-Ca Pyroxene (Fs_1.4±0.3Wo_45.2±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 (2020) Meteorit. Planet. Sci. 55, 1146-1150

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Photos:

Credit	Photos
Photos uploaded by members of the Encyclopedia of Meteorites. (Caution, these are of unknown reliability)
Robert Smart
Public domain photographs:
Daniel Sheikh

Geography:

Coordinates:

Unknown.

Statistics:
This is 1 of 9116 approved meteorites from (Northwest Africa) (plus 1873 unapproved names)

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