Northwest Africa 6888 (NWA 6888)        24°38.57’N, 14°41.27’W

Ri­­o­­ de Oro, Western Sahara

Found: 2011 May 28

Classification: Lunar meteorite

History: The meteorite was found by anonymous finder on the Sueilila (Zwilila) limestone plateau, ~40 km E of Hassi Lakra (Playa del Cordero) station, in the desert.

Physical characteristics: One brownish-grey to dark green stone weighing 208 g in total, with no fusion crust.

Petrography: (Lorenz C.A., Ivanova M.A., and Demidova S.I. Vernad.) The meteorite is polymict, melt matrix breccia, consisting of numerous mineral and lithic fragments embedded in a fine-grained devitrified matrix. Lithic clasts dominated by melt breccias, granulites, anorthosites, gabbro, gabbro-norites, troctolites and VLT-like basalts. Rare spherules of devitrified glass occur. The size range of the clasts is 0.02-9 mm; the main minerals are pyroxene and feldspar; minor - olivine, silica, chromite, ilmenite, Zr-armolcolite, troilite, and FeNi metal.

Geochemistry: (Kononkova N.N., Vernad, EMP) feldspar An_91-97Ab_2.8-6.0; clinopyroxene En_7.7-68.3Wo_5.1-42.0, orthopyroxene En_44.4-75.0Wo_2.6-4.9 (FeO/MnO = 60.03), olivine Fo_4.7-63.3 (FeO/MnO = 87); ilmenite (MgO 0.24-4.02 wt%), Al,Ti-chromite (TiO₂ 8.4 wt%, Al₂O₃ 8.2 wt%) and ulvospinel. FeNi metal: 0.68-9.51 wt% Ni; 0.40-2.27 wt% Co; sulfide is troilite.

Classification: Lunar (regolith breccia). The grade of weathering is moderate.

Specimens: A total of 21.7 g of sample and two thin sections are on deposit at Vernad. An anonymous finder holds the main mass of the meteorite.