Hi Karat While Gold

[scrappydog1958]

Is the best way to make hi karat gold material to just edit the existing 24 kt gold and change color, or are there other optical parameters that might be required?

[Peter.Chaushev]

This is a very late response but just wanted to confirm you are on the right track. Adjusting the Diffuse color and Reflection IOR should suffice. White gold in particular would be with lower kt value depending on its chemical composition, so starting with a preset library material, such as "Gold 14k", and fine-tuning it should work fine.

Hope this article can also help: https://www.chaos.com/blog/understanding-metalness