A lump of lava (more than 32 MM across) that has been ejected from a volcano during an eruption.

Volcanic bombs are named for their shape which is aquired in trajectory:
  • Bread-crust bombs have a glassy crust that is criss-crossed with cracks.
  • Spindle bombs have a tail formed by the spinning of the bomb as it falls
  • Rope bombs and ribbon bombs are twisted strands of elongated and solidified lava
  • Cannonball bombs are solid, rounded lumps of lava that take shape by abrasion as they bounced to rest.