In contrast to earthen excavations, stone caves or excavations are less likely to collapse, even without supports. They can be a little larger and more extensive. There's no need for a GM to make d6 rolls for collapse in most cases unless the rock is crumbling. An earthquake, of course, changes all that. In general, though, adventurers would have to expand a stony subterranean chamber by at least a fourth to trigger a d6 roll, and that will take much longer than digging through packed earth.
Caves, of course, are completely natural and unlikely to have supports, although they may have constructions in them, like a palisade. As a quick rule of thumb, the space in a cave won't be more than four times longer in any direction than it is high; long or large caves will either be twisty or broken by by natural stone columns. Excavations may have supports, especially in spaces that extend 40 feet or more in any given direction.
Add +2 to a d6 collapse roll if there is an earthquake. Subtract 1 from the roll if there are supports.
Caves and stony excavation are more likely to be damp, which can trigger d6 rolls to avoid slipping in a chase or when near a drop-off or chasm. Exceptionally damps caves will drip water, which may trigger d6 rolls that extinguish exposed flames. However, this can provide an emergency source of liquid for the thirsty.