Advanced (I think) Photoshop Effects (grunge, pics inside)

Ok ok now dont just say grunge brushes… cause i have tried this… but i cant NOT get these effects…

ok the first one… its behind the title,/flowerish vector thingy… its basically the background. How do i acheieve this stoney effect. it almost looks like a real slab of grainy stone… where each peice is unique and individual…

then here again

basically its done throughout the front / back… on the back there is a red peice (upper left of the flyer) thats more specific of what i want to do. but how eich peice is individual and unique. and realistic looking…

maybe some tutorials for this effect ? or an explanation? thanks !!!