Northwest Africa 10910 (NWA 10910)

(Northwest Africa)

Purchased: 2016

Classification: R4-6

History: Two stones weighing 56.7 and 60.1 g were found and subsequently purchased in Morocco in 2015. Don Cline and John Sinclair acquired the samples from a meteorite prospector at the Tucson Gem and Mineral Show in February of 2016.

Physical characteristics: Samples have an ovoid shape with a few shallow regmaglypts. Sample 95% covered by a lightly weathered dark brown-black fusion crust, which contains contraction cracks. Small cracks in the fusion crust from both samples show interior is dark green in color.

Petrography: (A. Love, App) Sample has a brecciated texture. Chondrules have an average diameter of 390 μm (N=86). Some clasts display distinct chondrules in a recrystallized matrix while other clasts have been completely recrystallized and lack recognizable chondrules. Chondrule olivines show undulatory to weak mosaic extinction and some contain irregular and multiple sets of planar fractures. Olivine chondrules and fragments are dominant. Accessory minerals are pentlandite, pyrrhotite, Cr-spinel and Na-feldspar.

Geochemistry: (A. Love, App) Olivine: Fa_41.2±0.3, N=16; low Ca pyroxene Fs_32.3±6.3Wo_1.7±0.4 (Fs_11.3-34.7, N=12); high-Ca pyroxene Fs_12.3±0.3Wo_49.4±0.5, N=5.

Classification: Rumuruti chondrite (R4-6, S4, W0). Mineral compositions and extensive sulfides suggest this is an R chondrite. Brecciated texture, equilibrated compositions of olivine and poorly equilibrated composition of pyroxenes suggest host is composed of a mixture of type 4 and higher petrologic grades of materials. Textures and equilibrated compositions within clasts suggest clasts are R5-6.

Specimens: PARI holds the main masses (116.8 and 29.2 g). A 22.1 g type specimen and one polished thin section are on deposit at App.