Machtenstein        48°17.043’N, 11°18.810’E

Bayern, Germany

Found: 1956

Classification: Ordinary chondrite (H5)

History: Found by a landowner during farming in his field in 1956 (or some years later) near Machtenstein. Because of its unusual appearance, the stone was kept by the finder in his farm house. In 1982 the stone was given to a friend, who preserved it for several decades, until it was rediscovered and recognized as a meteorite in 2014.

Physical characteristics: Total mass 1422 g, type spec 21.7 g, one polished thin section, one polished thick section, one thick section with raw sawed surface, density 3.39±0.05 g/cm³, fusion crust absent due to weathering.

Petrography: R. Hochleitner (MSCM): Size of chondrules 0.2 to 1 mm; shock stage S2, uneven darkening of olivines; recrystallized matrix is mostly hypidiomorphic, grains 0.01 to 0.5 mm, dominant matrix minerals olivine and pyroxene; feldspar grains up to 50 μm, metal; kamacite and taenite up to 50 wt% Ni, Co in kamacite 0.46±0.1. Metal (esp. kamacite) altered to goethite/limonite up to 40%. Massive veining of iron oxides in cracks is visible;  the outer parts are heavily weathered, with up to 70% altered kamacite.

Geochemistry: Dominant minerals are olivine, orthopyroxene, kamacite, troilite, taenite, feldspar, olivine Fa_18.7, orthopyroxene Fs_16.5Wo_0.01, kamacite 7.0±0.23 wt% Ni, 0.46±0.1 wt% Co.

Classification: Ordinary chondrite, H5, S2, W2/3.

Specimens: Type specimen, one polished thin section, one polished thick section, and one EMP sample are deposited in MSC). One specimen of 11.4 g, Heinlein.