Northwest Africa 1241

Libya

Found 2001 August 11

Achondrite (ureilite)

A single stone of 282 g was found by an anonymous finder in the Libyan desert. Classification and mineralogy (F. Wlotzka, MPI, and M. Kurz, Kurz): coarse olivine and pigeonite grains (up to 1 mm) are set in a pavement texture of smaller olivines containing finely dispersed metal grains. Coarser white reflecting grains are suessite, (Fe,Ni)3Si, with 13 wt% Si, 2.5 wt% Ni (range 1–4 wt%), and 1.1 wt% Cr. This mineral is abundant and occurs in blocky grains or interstial vein-like forms. No kamacite and no troilite were found. Olivine cores, Fa17–20 (0.7–1.7 wt% Cr2O3, 0.2–0.6 wt% CaO), rims are reduced to Fa1–10; pigeonite, Fs4–22Wo4–15En74–87, and 0.6–1.2 wt% Cr2O3. Carbonaceous matrix is rare, graphite occurs in fine-grained patches. The stone is, in contrast to North Haig, not brecciated. Weathering is minor, except for carbonate and oxide veins. Specimens: type specimen, 20.5 g, MPI; main mass is with the anonymous finder.