Pushing faces out, as a region or one at a time

Inset with Mode set to Region, Thickness 0 and a non-zero Depth pushes a whole connected selection out as one block. Neighbouring selected faces join into a single island, and only the outside edge of that island gets new side walls.

Extrude Tiles is the other half: every face gets its own box along its own normal. On a closed solid that pulls the object apart into separate slabs, which is the effect you want for shattered plating and not for a rock.

Two things decide how it looks. Run Set Faces in Quad mode first, or a subdivided side counts as one face and the whole side moves. And the shape you start from picks the species: the same recipe gives a faceted ball from an icosahedron and a chunky boulder from a segmented cube.

How you select changes the character more than the depth does. White Noise into Compare scatters isolated blocks. Voronoi or Noise into Compare clusters them into massifs, because neighbouring faces read similar values from a smooth field. The faces you did not select become the recesses, so you get concavity for free.

Set Depth Direction to Axis when you want every island to move the same way instead of along its own normal. That is the blocky mesa, the basalt column and the terraced strata. The axis is local, so a Transform after it turns the terraces with the model.