How much does a gallon of lava weigh?

Answer 1

That would depend on the type of lava. Darker mafic lavas (the kind that you imagine bubbling along in a goopy stream) will have heavier minerals, and be denser. This makes a heavier gallon!

Answer 2

A milk crate of small-sized lava rocks weighs about 40-45 pounds.

Answer 3

The physical characteristics of that unique substance are such

that the more of it you have, the more it weighs.