
Mesosiderites are somewhat of an enigma. The most widely accepted theory of mesosiderite formation is they result from an impact of a semi-molten metallic core of a previously shattered asteroid with the basaltic surface of a larger, intact asteroid.
NWA 15346 was a single large stone found in 2020 in the Western Sahara Desert and is exceedingly fresh. The cut surface reveals pervasive fine-grained metal and sulfide inclusions and a bounty of dark fine-grained silicates. Scattered larger silicates accent this otherworldly abstraction. The silicates are primarily comprised of pyroxene with a bit of plagioclase and trace amounts of silica, merrillite, chromite and schreibersite. Metal and troilite make up approximately 40% of this meteorite and are primarily segregated into irregular ameboid domains >1 mm, although there are scattered smaller (~10 μm) grains throughout the silicate domains.
While mesosiderites represent less than 0.5% of all meteorites, the B2 class is more rare still: of the 316 documented mesosiderites, only nine are designated type B2.
18.2″ x 12.7″ x 0.1″ and 1391 grams (3 lbs). An artifact in the Future Ventures 🚀 Space Collection.

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