Lunar Meteorite: Northwest Africa 6831

from The Meteoritical Bulletin, No. 108

Northwest Africa 6831 (NWA 6831)

(northwestern Africa)
Purchased: 2009
Mass: 20 g (1 piece)

Lunar Meteorite

History: The meteorite was purchased in 2009 from a local meteorite dealer in Erfoud, Morocco.

Physical characteristics: Dark greyish individual without fusion crust.

Petrography: (Ansgar Greshake, MNB) The meteorite is a relatively fine-grained fragmental breccia composed of up to 1 mm sized lithic and mineral clasts consolidated by a vesicular vitreous groundmass. Lithic clasts include basaltic and melt clasts; mineral clasts are dominantly calcic plagioclase, ferroan olivine, low-Ca pyroxene, pigeonite, and Ca-pyroxene. Minor phases include chromite, ilmenite, fayalite, and FeS.

Geochemistry: olivine: Fa_40.7±5.5 (Fa_31.7-50.4, n=25, FeO/MnO=82-102); low-Ca pyroxene: Fs_23.7±0.2Wo_3.5±0.3 (Fs_23.5-24.0Wo_3.2-4.0, n=5, FeO/MnO=55-66); pigeonite: Fs_29.3±1.3Wo_11.7±2.1 (Fs_27.1-31.7Wo_8.3-14.8, n=9, FeO/MnO=47-61); Ca-pyroxene: Fs_60.7±3.6Wo_24.5±2.0 (Fs_54.6-67.3Wo_20.1-26.9, n=9, FeO/MnO=66-75); calcic plagioclase: An_92.6±1.3 (An_90.1-93.8, n=20).

Classification: lunar (feldspathic breccia)

Specimens: Stefan Ralew.

Randy Says…

I have not studied NWA 6831. The plagioclase is more albitic than is typical for a feldspathic lunar meteorite.

More Information

Meteoritical Bulletin Database

NWA 6831