Vesicular basalts are essentially intermediate lithologies between basalts and scorias. Scorias are basaltic rocks with numerous small gas bubbles. Vesicular basalts are basaltic rocks having a few relatively large gas bubbles. Vesicular basalts are much denser than scorias (some scorias will float on water; vesicular basalts won’t do that).
Vesicular basalt (3.1 cm across)