Hello, I’m a rookie at blender so i was following a Tutorial on making a Photo Realistic Ring https://www.youtube.com/watch?v=zqhi8q4EGZk And i wanted to change the texure of the Turqoise

to an Opal Texture such as these stones.

I would greatly appreciate any help or suggestions on how to achieve this effect!! Keep in mind im a rookie so a picture of your nodes texture or a copy of your blender file would be most helpful!
Here is a copy of my blender file : Turqoise_Ring.blend (668 KB)