The largest cross-sectional slice of the NWA 7397 main mass.

Meteorites from Mars are among the most exotic substances on Earth. Martian meteorites share the following fundamental characteristics: they exhibit an unusually young crystalline age (so they cannot be from Earth); they contain water-bearing minerals (so they cannot be from the asteroid belt - the origin of 99.9 percent of all meteorites); there is evidence of a planetary sized gravitational field on their crystalline structure (which then makes the most likely candidates of origin our two closest neighbors - Venus and Mars). The link to Mars was speculative until an analysis was conducted on the glassy inclusions of two suspected Martian meteorites. In this glass were tiny voids, and in these voids were tiny volumes of gas. In 1997, the technology existed to analyze the gas - and it matched perfectly with the signature of the Martian atmosphere as reported by NASA's Viking Missions to Mars. The delivery mechanism was an asteroid impact which jettisoned material off the Martian surface into an Earth intersecting orbit. This is a select slice of a rock from the planet Mars.

NWA 7397 contains large ovoid crystals - many of which are chatoyant. The large salmon-hued oikocrysts (crystals that contain other crystals) are composed of low calcium pyroxene, which enclose crystals of olivine and chromite. The reverse is blanketed in fusion crust, an artifact of the meteorite's fiery descent through Earth's atmosphere (where temperatures reached during frictional heating are hotter than the surface of the sun!).

NWA 7397 shares the compositional and isotopic fingerprint of other Martian meteorites. The determination of Martian origin is the result of research having been conducted by hundreds of scientists throughout the world. The lead author of the scientific abstract on <a href="https://www.lpi.usra.edu/meteor/metbull.php?sea=nwa+7397&sfor=names&ants=&nwas=&falls=&valids=&stype=contains&lrec=50&map=ge&browse=&country=All&srt=name&categ=All&mblist=All&rect=&phot=&strewn=&snew=0&pnt=Normal table&code=55749" rel="noreferrer nofollow">NWA 7397</a> is Dr. Anthony Irving, the world's foremost classifier of planetary meteorites.

140mm across, 51.4g SNC - Shergottite / Mars Rock