Enormous Meso-B Meteorite NWA 15346 — 17x12". 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. 
<p>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 &gt;1 mm, although there are scattered smaller (~10 μm) grains throughout the silicate domains. 
</p><p>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.
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438 x 311 x 3mm (17.25" x 12.25" x 0.1") and 1391 grams (3 lbs). An artifact in the Future Ventures 🚀 Space Collection.
Steve Jurvetson
CC BY 2.0
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