Northwest Africa 11637 (NWA 11637)

Morocco

Purchased: May 2017

Classification: Iron meteorite (IIAB)

History: On May 21, 2017, during the China (Hunan) Mineral and Gem Show in Chenzhou, China, Wang Chen purchased 3 individual specimens (3096 g, 1100 g, 172.3 g) from a Moroccan dealer attending the show.

Physical characteristics: The three pieces have a dark brown exterior with minor rust-colored spots.

Petrography: (C. Herd, UAb) Optical investigation of a ~4 × 5 cm polished and etched surface reveals a well-developed Widmanstatten pattern consistent with a coarsest octahedrite (3.6±1 mm; n=6). No obvious inclusions were noted. Terrestrial alteration has occurred along fractures connecting to the exterior.

Geochemistry: ICP-MS data, using sample of North Chile (Filomena) as standard (C. Herd and G. Chen UAb): Ni = 5.7, Co = 0.47 (both wt%); Ir = 2.3, Ga = 54, Ge = 137, As = 4.8, W = 2.5, Re = 0.15, Pt = 18.3, Cu = 139, Au = 0.5 (all μg/g).

Classification: (C. Herd, UAb): IIAB iron, through comparison of bulk composition with data from Wasson et al. (2007).

Specimens: Type specimen consisting of two representative slices (13.5 and 11.8 g) at UAb. Wang Chen holds the main mass (2910 g), Wang Ziyao the 1100 g individual, and Mendy Ouzillou holds the 172.3 g individual and a 117.5 g end cut from the main mass.