This dark gray igneous rock is glassy and elsewhere contains small vesicles and flow bands.What type of rock is this?

Question

Quizplus · Accepted Answer

The description of the rock as "glassy" and containing "small vesicles and flow bands" suggests that it is a volcanic rock. The dark gray color indicates that it is likely to be an intermediate to mafic rock type. Basalt would also be a possible choice, but the presence of vesicles and flow bands suggests that it is more likely to be rhyolite or obsidian. Welded tuff refers to a type of pyroclastic rock formed from the consolidation of volcanic ash, which does not match the description given. Volcanic breccia is a rock composed of fragmented volcanic material, which also does not match the description given.

This Dark Gray Igneous Rock Is Glassy and Elsewhere Contains