The term is used for the material while it is in the air, after it falls to the ground, and sometimes after it has been lithified into rock. Depending on the eruption, most volcanic ash consists of small fragments of volcanic glass that were torn apart by violently expanding bubbles of gases. Informational website about noaa's volcanic ash advisory centers and their monitoring of volcanic ash across significant parts of the world.
BombshellBlaze
Volcanic ash is a mixture of rock, mineral, and glass particles expelled from a volcano during a volcanic eruption
The particles are very small—less than two millimeters in diameter
They tend to be pitted and full of holes, which gives them a low density. This web encyclopedia provides information on the impacts of volcanic ash and mitigation strategies for dealing with them