Procedural Rock Texture in Cycles

Support Materials and Textures
1

I’m somewhat new to using procedural texturing. I feel like it’s worth learning since I keep getting mediocre results using images, like problems with tiling and displacement. My aim right now is to recreate the following image for coloring and bumping:

http://www.cgtextures.com/thumbnails/textures/Rock/SmoothErosion/RockSmoothErosion0015_11_thumblarge.jpg

So I’m starting with a voronoi texture with generated mapping and a noise texture. My three big goals are to give a jagged look to the cells (possibly the easy part, like noising them up?),
widen the gaps between the cells (I’m guessing the hard part…maybe a fractal?),
and add some lighter color near the cracks.

I followed a fantastic procedural rock from El Brujo at http://materialw.wordpress.com/materials/rock-material/, but that’s a sandstone look. This is sort of my aim, a cracked stone texture for text, but ideally not this cartoony.

http://us.123rf.com/400wm/400/400/koya79/koya791202/koya79120201165/12557826-letter-w-cracked-stone-3d-font.jpg

I’m pretty sure I’m out of my depth, but what do y’all think?

2

Thanks @Didgeboy287. There is also a blend file there.

3

Ah, yes, true. When I first was writing this I mentioned that it wasn’t originally yours, but somehow in the editing I left that part out. My apologies to you both.

4

How did you achieve the one you made as I wouldn’t mind experimenting with something like that.
My basic issue is achieving the voronoi cracks simply coming in from the edges.

Thanks.