Very much the same as a shader set I'm working on to share, aswell. Both for voronoi cracks and caustics/waves.

That's nice seafoam distribution, I'm trying to properly distort the voronoi with smoother fractals for my caustics shader, you seem to be quite close to what I'm trying for with your foam, a little less colour roughness would be ideal for applying to my warped voronoi caustics. It seems your using the voronoi as the inverted blendshader of a fractal here, it's working nicely.

If you stick a 'complement colour' function after the voronoi you'll negate the need to negate the blending shader but you've probably already got that, it's impossible to tell with just a rendered image, it just seems like that from the first post's image where the cells are white, instead of the cell's borders. (a colour adjust shader is probably needed aswell as a comlement colour, in most cases the white really overpowers the black without one).

Liking your results so far...