Scoria is a lava rock that generates below y level 30 in every biome. Be careful, not all of the lava at that depth has cooled into stone.

Limestone is a porous sedimentary stone that generates in Midnight forests. Be careful though, as maggots like to make their home in it.

Slate is a hard, layered stone that generates in Petrified Forests. Quartz is often found generating in this kind of stone.