Well, I don't have 3D, so I don't know the limitations, but make it a little grainy, jagged, almost random. Those look like crystals, so have sharper edges, maybe a little rougher. Try finding a few photos of natural crystal formations, or not, that's probably too much work for 1 sig. Of course, the grid you have might be messing me up, but it still looks nice.
Like this.
Sorry, I'm a perfectionist.