Above the old Sutter's Mill near Coloma, California, it literally rained meteorites last April 22, 2012. The small fragments could be heard clanking and bouncing from rooftops, in a similar fashion to the famous Canadian Grimsby meteorite of 2009.
Dr. Peter Brown and PhD candidate Elizabeth Silber were on a large international team that has published some astounding results of preliminary research on the Sutter's Mill meteorite in Science Magazine.
It turns out that this object is a carbonaceous chondrite meteorite of the Carbonaceous-Meghei class (CM), containing some of the oldest known material in our solar system.
Brown and Silber studied the infrasound shock waves that were produced as the meteorite entered the atmosphere over California.