AN INCREDIBLY RARE DISCOVERY – THE LARGEST PIECE OF MARS ON EARTH, EJECTED FROM THE MARTIAN SURFACE B🐲Y A MASSIVE ASTEROID STRIKE, JOURNEYED 140 MILLION MILES THROUGH SPACE, AND HURTLED THROUGH EARTH’S ATMOSPHERE BEFORE CRASHING IN THE SAHARA DESERT

Discovered on 16 November 20ꦬ23 by a meteorite hunter in Niger’s remote Agadez Region, NWA 16788 is approximately 70% larger than the next largest piece of Mars found on Earth. Pieces of Mars are unbelievably rare: of the more than 77,000 officially recognized meteorites, only 400 are Martian meteorites, with an approximate combined weight🃏 of 374 kg (825 pounds). Weighing 24.67 kilograms, NWA 16788 represents approximately 6.5% of all Martian material currently known.

NWA 16788 is covered in a reddish-brown fusion crust giving it an unmistakable Martian hue. Regmaglypts, or surface🌄 depressions formed by frictional heating during rapid descent through Earth’s atmosphere, are also visible on the surface of the meteorite. NWA 16788 shows minimal terrestrial weathering, indicating that its physical and chemical makeup have not been significantly altered since its arrival in the Sahara Desert. In other words, NWA 16788 is likely a relative newcomer here on Earth, having fallen from outer space rather recently.

A significant percentage (21.2% by volume) of NWA 16788 is composed of a glass known as maskelynite, produced when an asteroi𝓡d struck the Martian surface with such force that it metamorphosed the rock’s original feldspar through intense heat and pressure, also p🔯ropelling this piece of Mars off the surface of the planet. Given the severity of impact necessary to eject any material off the Martian surface and into space, researchers believe there are only approximately 19 craters large enough to be the potential origination points for Martian meteorites.

NWA 16788 is an olivine-microgabbroic shergottite, formed from the slow🔯 cooling of Martian magma and characterized by a course-grained texture composed primarily of pyroxene, maskelynite, and olivine. Only 5.4% of Martian meteorites are currently classified as either gabbroic or microgabbroic, making this a rare type of rock within the already extremely rare category of Martian meteorites. Because NWA 16788 also shares characteristics of poikilitic meteorites – that is, meteorites in which the crystals of one mineral are enclosed by the crystals of another mineral – current and future studies of this meteorite may lead to the revision of the Martian meteorite classification system, possibly bringing it into increased alignment with our more developed terrestrial rock classification system.

NWA 16788 was validated and published in the 113^th 💙edition of the Meteoritical Bulletin (2025), the journal of record for me꧟teoritical science. Prior to landing at Sotheby's, the meteorite was publicly exhibited at the Italian Space Agency in Rome during the 2024 European Researchers’ Night and in a private gallery in Arezzo, Tuscany. 

Texture of NWA 16788:

“Backscattered electron (BSE) images and optical mosaics reveal a millimeter-sized cumulate texture dominated by a homogeneous distribution of pyroxene (61.1 vol.%), maskelynite (i.e., shocked plagioclase, 21.2 vol.%), and olivine (15.3 vol.%) assemblages. Accessory phases include phosphates (1.4 vol.%), ilmenite + Fe-Cr-Ti oxides (0.8 vol.%), and pyrrhotite (0.2 vol.%). A poikilitic texture with olivine chadacrysts (⁓ 100 μm) enclosed by pyroxene oikocrysts (from 1 to 2.5 mm) is also observed. Pyroxene, olivine, and accessory phases exhibit numerous irregular cracks and fractures. A set of fractures oriented perpendicular to the elongate axes appears in pyroxene and olivine grains. Micrometric veins enriched in Ca-carbonate, likely resulting from terrestrial weathering, are found around shock-melt pockets.” (Shehaj et al., forthcoming, lines 286-96).

REFERENCES:

Franza, A.; Shehaj, X.; Pratesi, G. A Fistful of Mars Explo♏ring the Role of Martian Mete⛎orites in Cultural Heritage and Scientific Inquiry. Heritage 2024, 7, 6981–6997.

Shehaj, X.; Pratesi, G.; Ammannito, E. Rethinking Martian Meteorite Classification? A New Perspective From the Shergottite Northwest Africa 16788. 56^th Lunar and Planetary Science Coꦇnference, 10-14 March 2025.

Shehaj, X. et al. Northwest Africa (NWA) 16788: A New Olivine Microgabbroic She💙rgottite. Insights Into Martian Magmatism From the Largest Individual Meteorite From Mars. Forthcoming.