Here is the material zone for both the **diamond_base and the circlet** that I have.  This was not what was normally there. I used a chrome car texture and added that fresnal node to it.  What was originally there was a gold colour.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi