do mobs spawn on cobblestone??
they sure do. afaik only glass and in light they don't spawn, all other materials are spawnable, afaik that is.
What block can mobs not spawn on?
Mobs cannot spawn on blocks that are less than a full block in height. Areas covered in bottom half slabs will be unable to spawn mobs, no matter the light level, although double slabs, top half slabs and upside down stairs are still spawnable.
Can mobs not spawn on stone brick?
A player can spawn on any solid block which is not affected by gravity and is below the sky, so there are no blocks above it. Animals spawn on grass or dirt exclusively (block id 2 and 3). They also require a light level above 9 and at least 2 blocks of air above them.
