Mesosiderite – B2; The Sahara Desert, Western Sahara

Similar to lot 64. There are three different types of meteorites: Stones (see lots 5 and 40), Irons (see lots 21 and 26) and the rarest group, a combination of the two, Stony-irons. There are two classes of stony irons, pallasites, which contain extraterrestrial gemstones (see lots 18 and 44) and mesosiderites — like the specimen now offered. Mesosiderite formation remains somewhat of an enigma. The most widely accepted theory is that they result from the impact of a semi-molten metallic core of a previously shattered asteroid with the basaltic surface of a larger, intact asteroid.

Exceedingly fresh, the exterior rim of the specimen exhibits a desert varnish. The cut surface reveals pervasive fine-grained metal and sulfide inclusions and a bounty of dark fine-grained silicates. Scattered larger silicates provide further accent. Segregated metal and some brecciation is in evidence. These characteristics result in NWA 15346 having received a “B2” subclassification. While mesosiderites represent less than 0.5% of all meteorites, the B2 subclass is more rare still: of the 316 documented mesosiderites, only nine are designated B2. Moreover, NWA 15346 is the 11^th largest mesosiderite on record and now offered is a large partial slice with a long arcing rim of the meteorite’s external surface terminating at the cut base. Various sized silicates evidencing brecciation and a large bleb of metal at its center in a wondrous representation of an enigmatic meteorite.

Christie's would like to thank Dr. Alan E. Rubin at the Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles for his assistance in preparing this catalogue.

205 x 322 x 3mm (8 x 12.75 x 0.1 in.) and 989.7 g (2 lbs)