Northwest Africa 1925

Morocco

Found 2001

Achondrite (eucrite)

A single, 86 g, complete stone was purchased in Tagounite in 2002 April. Classification and mineralogy (T. Bunch and J. Wittke, NAU): gabbroic, cumulate eucrite; tabular crystals of plagioclase (<4 mm in longest dimension) poikilitically enclosed by large pyroxenes (up to 8 mm). Plagioclase is An₉₁ with melt inclusions of a silica polymorph, Mg-augite, and ilmenite. Complex pyroxenes consist of inverted pigeonite (Fs_52.5Wo_4.2) with broad (5-8 µm) augite exsolution lamellae (Fs₂₅Wo₄₁) parallel to (100) of the host opx and blebs of augite that exsolved prior to or during pigeonite inversion. In additon, relic patches of pigeonite contain fine augite lamellae parallel to (001). Chromite, Cr/Cr+Al = 63-73, pyrrhotite, and tiny inclusions in opx of Ni-poor metal (Ni = 0.48 wt%; Co = 2.28 %) are also present. No ilmenite or silica was found outside of melt inclusions. Shock level, S2/3; weathering grade, W1.  Specimens: type specimen, 17.2 g, NAU; main mass, MFarmer.