NWA 2650

Northwest Africa

Purchased 2004

Achondrite (cumulate eucrite)

A 2224 g complete stone that measures 189 mm x 112 mm x 82 mm at the widest points, with fresh crust was purchased in Erfoud, Morocco, Description and classification (T. Bunch and J. Wittke, NAU): cataclastic, cumulate eucrite; coarse-grained (plagioclase up to 7 mm and pyroxenes to 5 mm); zones of intense crushing with minor recrystallization; discontinuous melt veins and pockets. Plastic deformation and offset faulting in plagioclase; minor amounts of maskelynite; undulatory extinction, shock twinning, and reduced birefringence in pyroxenes; shock level, S3-5. Extensive development of albite, Carlsbad, and complex igneous twinning in plagioclase. Exsolution lamellae of subcalcic augite (Fs52.5Wo15.9) in inverted ferrohypersthene (Fs61.1Wo3.8) and separate grains of augite (Fs25.1Wo45.7), FeO/MnO of all pyroxenes between 32.2 and 34.8. Plagioclase, An90.8 and minor amounts of ilmenite and chromite, cr# = 68-75. Low weathering grade. Specimens: type specimen, 23.1 g, NAU; main mass, D. Schultz.

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