Basalt used in a sentence

Basalt in a sentence as a noun

The ancient remains of a great and enormous basalt structure, hmm?

I looked it up. Apparently bits of olivine are embedded in lots of kinds of rock, particularly basalt.

'Shiny' objects in volcanic fields are typically obsidian or some other form of basaltic glass.

Geographically, I'd expect an Andes-like volcano from the subduction of the pacific plate, but they're talking about rivers of basalt.