Created in Blender 2.4x using material and compositor nodes as a learning experience. Model is a simple icosphere with subsurf. All geometry is derived via displacement modifier, deriving values from the material nodes.
In compositor, the diffuse value was colored, blended, and added (or multiplied - this was a while ago!) back into the image to achieve the "bloom" glow.
Blend file available here for study: http://www.draeath.net/freeshell/blender/magmaball-v2.blend
Video animation: http://www.youtube.com/watch?v=ptUousRKsMs
