Clasts ( Greek κλάω (kláo): to break) are solid fragments of rock that result from the mechanical destruction of other rocks. They range in size from blocks to gravel and sand to silt and clay . Depending on the original rock, the clasts consist of rocks such as granite , gneiss or sandstone and limestone .
Pyroclasts are rock fragments that have arisen from a solid or liquid volcanic starting material through tearing or breaking (fragmentation) or through direct crystallization as a result of volcanic activity.
- Hans Murawski, Wilhelm Meyer: Geological dictionary . 11th edition. Elsevier / Spektrum, Heidelberg 2004, ISBN 3-8274-1445-8 , pp. 112 .