LEGO transparent 2-sided brick with thick non-transparent edges

I was looking for this like 5 days in a row all over the internet and yet no success.

Would anyone with good knowledge about creating realistic materials try to imitate this kind of material?

I am attaching a photos of real LEGO transparent plastic bricks: the most significant part - and probably the hardest to reproduce universally for all in just one material - I guess would be those edges where the transparent material should actually become mostly non-transparent and much more darker than the rest of the brick giving it feeling of a volume/mass instead of the UE4 empty gap in between the faces of the 2-sided object (LEGO brick).

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