Phonolite

Phonolite is an uncommon extrusive igneous rock, volcanic rock, of intermediate chemical composition between felsic and mafic, with texture ranging from aphanitic (fine-grain) to porphyritic (mixed fine- and coarse-grain).

The name phonolite comes from the Greek meaning "sounding stone" because of the metallic sound it produces if an unfractured plate is hit; hence the English name clinkstone.