I want to use whatever material we pick for our vanity countertop to create a "frame" of stone around the shower entry -- sill, jambs, the "sill" equivalent that is overhead, and a ~4" border all around the entry both inside and outside the shower.

But when I try to explain this over the phone, I'm not confident I'm being understood. Is there an industry term for this?

I've mocked it up with the software I'm using: