Lunar Meteorite: Northwest Africa 15655

Two sides of a piece of Northwest Africa 15655 (polished on right?). Photo credit: Shun-Chung Yang
Two sides of an endcut of one of the NWA 15655 stones. Width: 9.5 cm. Photo credit: Heritage Auctions

Meteorite Picture of the Day: Northwest Africa 15655

from The Meteoritical Bulletin, No. 112

Northwest Africa 15655 (NWA 15655)

(Northwestern Africa)
Purchased: 2022 March
Mass: 446.5 g (3 pieces)

Lunar meteorite (feldspathic breccia)

History: Three stones weighing 94.0, 103.1, and 249.4 g were purchased in March 2022 by Shun-Chung Yang and Juan Chen from a meteorite dealer in Algeria.

Physical Characteristics: Three stones with dark-brown fusion crust.

Petrography: (D. Sheikh, Cascadia) Sample is a breccia comprised of mm to cm-sized sub-angular lithic and mineral clasts set within a fine-grained fragmental matrix containing accessory ilmenite and merrillite. Clast lithologies identified include anorthosites, olivine norites, noritic anorthosites, and anorthositic norites.

Geochemistry: Olivine (Fa43.9±8.1, range Fa27.6-59.2, Fe/Mn=89±2, n=9), Low-Ca Pyroxene (Fs45.0±1.4Wo3.9±1.4, range Fs44.0-46.0Wo2.9-4.9, Fe/Mn=56±3, n=2), Pigeonite (Fs35.8±6.2Wo13.6±3.9, range Fs26.3-48.8Wo8.2-23.1, Fe/Mn=57±6, n=11), High-Ca Pyroxene (Fs20.3±1.5Wo38.9±2.3, range Fs19.3-21.3Wo37.2-40.5, Fe/Mn=49±4, n=2), Calcic Plagioclase (An96.3±1.3, range An92.4-98.7, n=20).

Classification: Lunar (feldspathic fragmental breccia) comprising a mix of FAN, MAN, and Mg-suite lithologies. An unusual 20 μm grain of near end-member enstatite (Fs0.4Wo1.2, Al2O3 wt. % ~0.6) was identified within the matrix.

Specimens: 20.09 g at Cascadia, main mass with Shun-Chung Yang and Juan Chen.

Randy Says…

I have not studied Northwest Africa 15655.

More Information

Meteoritical Bulletin Database

NWA 15655

Lunar Meteorites
List – ABC123 Order
List – Al2O3 Order