Northwest Africa 17025 (NWA 17025)

(Northwest Africa)

Purchased: 2024

Classification: Mesosiderite (group A4)

History: Purchased in 2024 by Matt Morgan from a meteorite dealer in northwest Africa.

Physical characteristics: Two identical stones, 280 and 370 g, found together. A portion of the exterior surfaces display black fusion crust. The remainder of the exterior are earlier broken surfaces, now mildly weathered dark brown with green pyroxenes and metal and oxidized metal patches exposed.

Petrography: (C. Agee, UNM) Microprobe and reflected light microscope examination of a polished mount shows pyroxene grains with poikilitically enclosed finer-grained plagioclase (~25% by volume of the silicate fraction) and small blades of silica. Scattered olivine grains were observed, some as large as ~2mm. Metal domains make up 25% of this meteorite, and consist of coarse kamacite and taenite and are segregated from the silicate domains. Minor ilmenite and Fe-sulfide are scattered throughout.

Geochemistry: (M. Spilde, UNM) low-Ca pyroxene Fs_25.9±7.3Wo_4.5±3.8, Fe/Mn=29±3 n=6; olivine Fa_27.9±4.3, Fe/Mn=45±2, n=3; plagioclase An_91.8±1.2Ab_7.7±1.1, n=4.

Classification: Mesosiderite-A4. A4 based on plagioclase and silica abundance, poikilitic texture of pyroxene+plagioclase, and the nearly complete segregation of metal and silicate.

Specimens: 21 g on deposit at UNM, Matt Morgan holds the main mass.