Pyroclastic rocks or pyroclastics (derived from the Greek πῦρ, meaning fire; and κλαστός, 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 explosive volcanic activity - such as Plinian or krakatoan eruption styles, or phreatomagmatic… (More on Pyroclastic)