Slate Stone 3D Model I would like to displace a plane with a texture of a slate image to get a realistic 3D stone model. It should be fractured, liked this image:

http://www.randomghost.com/post/86272286137/shrbr-fracture-series-by-flight404-on-flickr#=

Everytime I try to displace any plane (no matter how high the number of subdivides) I end up with something that resembles this:



And this does not look anything like a realistic slate model. Is there any other way I can use to transform the plane to achieve this effect ? Can I achieve the same effect with Cell Fracture and if so how can I do this ? 

Thank you very much.
If you are using Blender 2.78 (set to experimental)

You need to first take that image and blur it slightly. Then Make sure you subdivide your mesh and unwrap. Add a subserf modifier, click adaptive. Then set everything up as you see in the images below. 









You are getting those spikes because the image is not blurred.