Northwest Africa 1500

Morocco?

Purchased 2000

Achondrite (ureilite)

A nearly complete individual of about 3.3 kg with fusion crust patches was bought by meteorite hunters in Zagora. During the Tucson mineral show it was sold to a mineral dealer and traded to R. Bartoschewitz in April 2002. Mineralogy and classification (R. Bartoschewitz, Bart; F. Wlotzka, MPI): This monomict rock has a typical ureilite texture of equigranular olivines (0.2–0.5 mm, Fo₇₂, CaO, and Cr₂O₃ < 0.1%) set in black vein material with finely dispersed metal. Minor components are augite (Wo₄₅En₄₄) and orthopyroxene (Wo_2.2En₇₀), plagioclase (An₃₇), chromite (0.2–0.3 mm, 5% MgO, 12% Al₂O₃) and metal (1.5% Ni, 0.3% Si). The plagioclase grains are 0.5 to 3 mm across and in igneous contact with olivine, the larger ones poikilitically enclose rounded olivine grains. Oxygen isotope composition (R.N. Clayton and T. Mayeda, UChi): δ¹⁸O = +4.56‰; δ¹⁷O = +1.58‰ plot away from other ureilites. But ∆¹⁷O versus mg-number extends the ureilite trend. Specimens: type specimen, 20 g MPI; main mass, Bart.