(WIP post continued because of the 3 image limit)
For the texturing, I started off by baking a cavity map (dirty vertex colors) so I could see where all the details were in texturing mode. Then I just projection painted this image onto my model http://commons.wikimedia.org/wiki/File:Green_Sea_Turtle_(chelonia_mydas)_basking_on_Punalu’u_Beach.jpg
And then the crystals! Here’s the node setup for them…
had to zoom out for it all to fit in one screenshot. It looks more complex than it really is though
The top blue frame is essentially this node setup with a few extra nodes to make tweaking a little easier
The next three frames were for volumetrics.
-The red frame was an image texture combined with a voroni texture, just to get some variations
-The teal frame adds a vertical gradient, so it’s most dense near the bottom, and clear near the top
-The orange frame is just a procedural clouds texture for adding little specks
The green frame at the bottom is just for surface displacement
To get the glow, I ended up doing 2 things. First I rendered out a pass with the Emit node hooked up to the volumetrics. It looked really cool and rendered out surprisingly quickly. It didn’t really cast any light on the turtle shell gravel though, so I wrote a script to add a lamp inside every crystal. This render pass did what I wanted, but it was super noisy - so I used blender’s Despeckle node and combined it with the first pass in photoshop.