Pyroclastic rocks or
pyroclastics (derived from the , meaning fire; and , meaning broken) are
clastic rocks composed solely or primarily of
volcanic materials. Where the volcanic material has been transported and reworked through mechanical action, such as by wind or water, these rocks are termed
volcaniclastic. Commonly associated with unsieved volcanic activity—such as
Plinian or
krakatoan eruption styles, or
phreatomagmatic eruptions—pyroclastic deposits are commonly formed from airborne
ash,
lapilli and
bombs or
blocks ejected from the volcano itself, mixed in with shattered
country rock.