I'm following this video: <https://www.youtube.com/watch?v=d-zpR1E84nQ>

I have a black cube inside the crystal, but its quite hard to actually see it, I've tried to give it more of a glassy effect but cant quite get it to look the way I want.

Also my crystal feel blurry and not as sharp as I would like it

Could anyone offer any advice?

Crystal shading:
[![enter image description here](https://i.stack.imgur.com/T7sEt.png)](https://i.stack.imgur.com/T7sEt.png)

Render output:
[![enter image description here](https://i.stack.imgur.com/XrtOL.png)](https://i.stack.imgur.com/XrtOL.png)