Northwest Africa 1653

Northwest Africa

Found 2002

Achondrite (howardite)

A single stone of 376 g partly covered by fusion crust was found in 2002 by an anonymous finder in the Western Saharan desert and purchased in Zagora in 2002. Classification and mineralogy (A. Greshake, MNB; M. Kurz, Kurz): basaltic eucrite and diogenitic clasts are set into a clastic matrix; dark impact melt fragments are abundant and often show quench textures with radial or skeletal shaped aggregates; eucrite clasts contain plagioclase, An91.9 (range An86.2–95.7); pigeonite, Fs35.8–59.2Wo5.8–17.6 and augite, Fs29.9–55.6Wo22.8– 31.1; minor phases include silica, chromite, and ilmenite; diogenite clasts are composed mainly of orthopyroxene, Fs25– 41.4Wo3.1–4.9 and olivine, Fa27.7 (range Fa26.2–30.2); chromite and ilmenite are among the accessory phases; low degree of shock; low degree of weathering. Main mass with anonymous finder; type specimen 21.0 g plus two polished thin sections, MNB.