Q. about Creating a material for Faceted Ethiopian Opals

seeking for ideas on how to go about creating a material for translucent faceted Ethiopian Opals that I need to render in jewellery. the material’s refractive index would be 1.42 - 1.43
but the colours are not on the surface but scattered differently inside each stone…

Previously [with cabochon shaped opals] I simply mapped/painted an image of the actual stone onto the 3D object, that was ok, but here it will not work.

I was thinking about randomly distributing faces inside the objects and perhaps giving these random inner faces an emitter material in different colours…
But this seems very complicated. probably best to approach it from GH? I’d be very happy to learn and experiment, but will need some help where to start.

Just to mention that, I think, I know how to [try and] do it in a limited way in another software, but it also seems like an excellent opportunity to explore GH and perhaps achieve better results …

[images bellow are random from google, but are similar to the actual opals I need to render.]

faceted ethiopian Opals

With thanks