Hey there @TajiyaO! Welcome to the community! I was coming to recommend Crystal Renderer but it looks like you’d already found it. Realistic crystal rendering is going to be somewhat difficult to find in a mostly video game based material economy. Using caustics you could probably get some great visuals.
A couple users have a few examples or directions they took on this thread, though it’s older:
Here’s a video that could get you started with a less realistic setup, and you could add more realistic features as you go:
Alternatively, you could start with a free glass material and try to modify it to suit your needs:
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