Sadly no. There’s light coming from top and bottom but this is a 1 block thick wall and it’s not acceptable to have gleam or chiseling on the back of it.
EDIT Hmm I might look at some kind of decoration on the inside though. It just can’t mess with the wall. It’d an inorganic farm and I can’t have light leakage so chiseling on the outside means the inside has to be flat.
IDK why it didn’t occur to me but I think you may have nailed it. It’s those bars on the top and bottom turning me off those diamonds, and a bit of gleam light helps things.
It’s pretty bright around here, and I don’t want to change the wall blocks seen from the inside.
I’m quite happy with this change right now. It’s mostly the bar/border on the vertical gems that was really making it look bad IMO.
you can chisel them into the same sort of diamond shaped blocks that you see other stuff carved into. You can see what’s inside it pretty well though so even if you wanted them free floating, adding gleam or something to make it bright would be visible, crating a layered effect more than a gem effect I think.