To make this photo I used this tutorial from Indy Mogul to make the rocks, only that instead of covering them with newspaper I used a layer of paper towel and white glue. I did this so that when I poured the casting plaster on the "rocks" it wouldn't filter through the holes that I left with the masking tape.
you can see the process that I followed here:
Camera: Canon 40D
Lens: Sigma 17-35 DG HSM
Flash: Lumopro LP160 @ full power and a Clairex Flash