I think I've posted this picture before. It shows the detail of the matrix that is created on the surface of the beads in BOTH the blue dyed and the plain white. I've never seen this process. I can only guess that it's done after the beads are cut with heat/cool and a brown dye that penetrates a short way into the stone. I'll start asking about the process when I next visit Chinese stone factories. I don't think it is much of a secret process anymore.

The blue dye does penetrate the bead, nearly all the way in most cases. Some beads have white areas. I'm not sure if this is because the dye does not penetrate there or because of some problem in the process. I see that mostly on the nuggety stuff they call cauliflower or brain nodules. The nuggety stuff is not always crazed with the brown dye. It's often seen with black dye (shoe polish?)tumbled into the crevices.

I wonder how similar the enhanced matrix process is to the process that produces the crazing on the Tibetan style agates discussed in the start of this thread?