Granite
From Memory Alpha, the free Star Trek reference.
Granite is a coarse-grained igneous rock that makes up most of the landmasses on Earth.
The headquarters of the Alliance on Turkana IV is located beneath two kilometers of solid granite. (TNG: "Legacy")
On Celtris III, there is a sheer granite cliff five hundred meters high in a cave, on the way to the Cardassian base. (VOY: "Chain of Command, Part I")
The underground Vidiian base on Avery III is only accessible through tunnels, disguised by force fields that mimic granite walls. (VOY: "Faces")
A Garan mining colony in the Delta Quadrant was excavated from granite. (VOY: "Macrocosm")
