Main-group pallasite
Main-group pallasites are the largest pallasite group, with olivine crystals set in metal similar to IIIAB irons.
Main-group pallasites are by far the commonest pallasites, making up the large majority of known examples. They consist of olivine crystals, often golden-green and centimetres across, set in iron-nickel metal. Famous examples include Brenham from Kansas, Imilac from Chile, Esquel from Argentina and Fukang from China.
Their metal is chemically similar to the IIIAB iron meteorites, and their olivine has a fairly uniform composition of roughly 11 to 14 per cent fayalite. These features suggest they formed where a metal core met an olivine-rich mantle. Some researchers favour a core-mantle boundary inside one asteroid, while others propose that molten metal from an impactor was injected into the olivine mantle of another body.
Cloudy-zone magnetism in some main-group pallasites suggests their parent body had a magnetic field generated by a molten core. On slices, the olivine can be translucent and beautiful, making these among the most sought-after meteorites.
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