a clump of lava, ejected during an eruption in a liquid or plastic state, which takes on one or another form in flight. Volcanic bombs are 1 cm to 7 m long. The most important of the many forms of volcanic bombs are the waferlike forms, characteristic of very liquid lava, clumps of which are flattened as they fall to the earth; twisted, spindlelike, pearlike, globular, and ribbon-shaped forms, characteristic of low-viscosity basaltic lavas, which harden in flight; and round or irregular multifaceted clumps of lava covered with a network of cracks—bread-crust bombs— characteristic of hardened acidic and andesite lavas.