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Northwest Africa 12856
Basic information Name: Northwest Africa 12856
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12856
Observed fall: No
Year found: 2014
Country: (Northwest Africa)
Mass:help 468 g
Classification
  history:
Recommended:  Eucrite    [explanation]

This is 1 of 441 approved meteorites (plus 1 unapproved name) classified as Eucrite.   [show all]
Search for other: Achondrites, Eucrites, and HED achondrites
Comments: Approved 21 Sep 2019
Writeuphelp
Writeup from MB 108:

Northwest Africa 12856 (NWA 12856)

(Northwest Africa)

Purchased: 2014

Classification: HED achondrite (Eucrite)

History: Collected by nomads in Western Sahara and purchased by Parco Astronomico delle Madonie from Giorgio Tomelleri in 2018.

Physical characteristics: A single piece weighing 468 g partialy covered with a black fusion crust. The cut surface displays scattered CAIs.

Petrography: (V. Moggi Cecchi, G. Pratesi, UniFi); The thin section analyzed displays a basaltic texture. Orthopyroxene is the major phase, with crystals 100-160 μm in width; minor clinopyroxene and anorthitic plagioclase are visible. Exsolved low-Ca pyroxene crystals with fine (5-7 μm) pigeonite exsolution lamellae can be observed. Minor phases are ilmenite, troilite, chromite, and FeNi metal.

Geochemistry: EMP (V. Moggi Cecchi, G. Pratesi, UniFi); Calcic plagioclase (An87.0±1.2Or0.4±0.2, n=4); low-Ca pyroxene (Fs58.0±1.3En34.3±0.3Wo7.7±0.1; n=6; Fe/Mn=49.9±0.5); diopside exsolution lamellae in orthopyroxene (Fs44.3±3.0En33.1±0.1Wo22.6±1.4; n=6; Fe/Mn = 39.1±0.5).;

Classification: Eucrite with medium degree of shock and medium degree of weathering.

Specimens: A total of 20.2 g specimen is on deposit at MSN-FI. Parco Astronomico delle Madonie holds the main mass.

Data from:
  MB108
  Table 0
  Line 0:
Place of purchase:Erfoud
Date:P 2014
Mass (g):468
Pieces:1
Class:Eucrite
Shock stage:medium
Weathering grade:medium
Ferrosilite (mol%):58.0±1.3 (n=6); 43.9±3.0 (n=6)
Wollastonite (mol%):7.7±0.8; 22.3±1.4
Classifier:V. Moggi Cecchi, G. Pratesi, MSN-FI
Type spec mass (g):20.2
Type spec location:MSN-FI
Main mass:Parco Astronomico Madonie - Isnello
Finder:Anonymous
Comments:Submitted by Vanni Moggi Cecchi
Institutions
   and collections
MSN-FI: MUSEO DI STORIA NATURALE DELL'UNIVERSITA' DEGLI STUDI DI FIRENZE Via Giorgio La Pira, 4 – 50121 FIRENZE, Italy; Website (institutional address; updated 14 Jan 2015)
UniFi: Università degli Studi di Firenze, P.zza S. Marco, 4 - 50121 Firenze, Italy (institutional address; updated 14 Sep 2013)
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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