Silver diamond ring. Model file contains ring, diamond and ring case
Ring. PBR silver texture. If you wish you can choose a gold, but I prefer silver
Diamond. Diamond material uses light dispersion effect. By changing the IOR, you can change the material. Now it is 2.418
Case. Velvet material is used for the case. Its color can be changed to your preference in the shader settings menu
The render was on an old processor, so the dispersion effect on the finished images doesn't look quite correct. Sometimes blurry, opaque, the glow does not look the way it should. With a better rendering the diamond will look realistic as it should
I decided to make it free. Hope you'll like it, but please let me know how good/bad it turned out :)