Cannonball bomb
Part of Hall of Planet Earth.
Visiting the Halls of Gems and Minerals? All visitors are required to join a virtual line once onsite.
Part of Hall of Planet Earth.
When the bomb hits the ground and hurtles down the slope, making a whirring noise, its corners become sheared, and the hardened form appears as a smooth, rounded lump.
Provided by Lava Beds National Monument and Jeff Dinnel, Tionesta, California