11.0g NWA 12949 Mesosiderite Meteorite - From An Asteroid!

Mesosiderites are a rare and intriguing class of stony-iron meteorites that look like someone smashed two very different rocks together and froze the result in time. They’re made of roughly equal parts metal (nickel-iron) and silicate rock, but instead of being neatly layered, the materials are jumbled together in a chaotic breccia. This messy structure suggests a violent history—likely massive impacts on an early asteroid that mixed material from its metallic core and rocky crust.

What really sets mesosiderites apart is that the metal and silicate portions didn’t form together under calm conditions. The minerals show signs of repeated heating, shock, and slow cooling, pointing to a long, complex life on a parent body that was battered but not completely destroyed. Because of this, mesosiderites offer scientists a rare glimpse into large-scale collisions in the early solar system and how planetary bodies were assembled—and sometimes torn apart—along the way.

About Stony-Iron Meteorites: Stony-iron meteorites, the rarest and often considered the most visually-desirable of the three meteorite categories, consist of iron-nickel, silicate minerals and gemstones. Within the stony-iron category, we have two different types: Pallasites and Mesosiderites.