Philipp Heck (Robert A. Pritzker Associate Curator for Meteoritics and Polar Studies) and collaborators from the University of Maryland and the University of California at Davis report on the rapid effects of terrestrial alteration of a pristine meteorite in a new article in Meteoritics & Planetary Science: The meteorite was seen falling in April 2012 over California’s Sierra foothills and landed near Sutter’s Mill (where the 1848–49 Gold Rush started). The authors compared pieces of the meteorites collected on dry ground just two days after the fall with pieces recovered later after a rain. They found clear differences in the contents of the trace elements rhenium and osmium between the pre-rain and post-rain specimens, showing that rain irreversibly affects meteorites. The results of this work emphasize how important it is to rapidly collect meteorites after they fall, so as to obtain the original composition of the meteorite to learn about early solar system processes. A recent example of a successful rapid collection was the Hamburg meteorite that landed in Michigan. The Sutter’s Mill meteorite that was used in this study was found by Robert Ward and donated to the Field Museum by meteorite collector Terry Boudreaux. Link to publication and to the story on the acquisition of the main mass of the 2012 fall.