Ghostship I showed the Principled BSDF for glass earlier in the thread. Your super shader is great but we've moved on past glass. It's dispersion as regards to diamond now. Unfortunately, your shader does not do dispersion. To the best of my knowledge; dispersion in crystal is not directly possible in cycles via shader node, and as such requires a work around as shown in the shaders above. If you have a diamond mat for your super shader by all means show us. That is the purpose of the thread.

Veda, looking good.

Miss B, the whole thing is based on an old BB thread for dispersion in Firefly I read some years ago. Might have been RDNA but I had thought it was here. You would do the same thing in Blender but with a colour ramp node you could increase the "fire" to include the entire spectrum in addition to the three primaries shown here. Add more wavelengths (colours) to the shader shown above by adding in more of the modular blocks. Glass, Glossy, Refraction. Any of those nodes can fake the dispersion. Refraction is the "correct" method as that is the physics that produces the effect in reality.