Is there a way to create a convincing diamond like material on a render made with the Blender Render engine? On the internet it seems to be dozens of tutorials for the Cycles Render engine, but as unbiased path tracing engine it's just way beyond what i'm looking for. Instead of realism I'm looking for a cartoonist looking refraction. Something akin to THIS instead of THIS. Thanks.
EDIT: I will make this into an answer if you want to mark it as solved.
You could try creating a gradient of the type you find by googling "gradient". Then UV unwrap your mesh and move (and rotate) the individual faces randomly around (with overlaps). Then simply apply the colors to the material. I haven't tried it, but you could give that a shot.
As suggested by user277143 I created a Gradient Texture using Photoshop and then overlapped the mesh to give an internal refraction effect. The effect is very subtle but is there. On the screen shot you can see that I added (perhaps too many) flat meshes as light sources, additional to a Sun and Hemi lights, in order to create some additional reflection. (The Material reflective is 0.25) I think it looks marvelous, just like I wanted it. :)