I couldn't help myself. This crystal combo I came across is amazing.
This is two meshes. The first (underlying) mesh is 1cm face extruded from the second. It uses a texture somewhat similar to the previous crystals, but having a noticeable gradient from top to bottom (which I might work on further), and has no alpha channel. I set the opacity on the mesh to 50%, and gave the texture an envmap to use to fill part of the opacity loss, using txi. I also set the self-illumination on the underlying mesh to 50% cyan, making it glow in the dark, and altering the overall color to aqua no matter when/how viewed.
On the second mesh, I used ChiliSkinner to create a polygon map, which I screen captured. Then I used a basic line drawing tool to draw just the face edges that I wanted to highlight. After blurring the map I created an alpha layer from the brightness, making the crystal faces very shiny, and the crystal frame not at all shiny. I then gave this texture its own txi which also gives it the same custom envmap, as well as sets the blending mode to additive.
In daylight, the crystal is mostly transparent, but you can see the glassy play of faces very easily. In the dark, the top really glows, and the bottom mostly flickers. The two layers of crystal face flashing join together to make a high contrast flicker, and their respective opacities join together to prevent a totally metallic look.
If had to change anything I would reverse the positions of the meshes and make the underlying crystal face less transparent, giving it a less glassy look, where you could also show more detail in the base texture. Alternately, a third layer outside the edge map layer could be applied using no opacity or alpha layer, and also setting the blending mode to additive, basically making a light map layer. You could then move the self-glow from the main mesh to the 3rd layer, and possibly use white instead of cyan.
