That's right, it was explosive rocks Vaal needed so often. To be fair, they were only "five hour energy" explosive rocks.
And I didn't have a name for it, but small planet syndrome
is a peeve of mine. It happens whenever we're dealing with pre-industrial natives. In "Errand of Mercy" and "Friday's Child," village elders are treated like planetary rulers and preposterously given the right to decide things they do not understand.