What is volcanic ash?

Is volcanic ash, ash – the product of combustion? Or is it very finely powdered rock?

Here ya go

Thanks, Dr. Lao. That’s what I thought.

(Incidentally, I have a little “gum machine” capsule of Mt. Saint Helens ash that my dad got after the 1980 eruption.)

There’s no straight, simple answer to that.

Volcanic ash is very finely powdered rock, but the stuff that’s left over after burning say, a tree or a lump of coal is pretty much the same stuff. All ash is basically rock - oxides of silicon, calcium, magensium, etc.