Best stoneware glue

A little OT for jewelry, but since this list is such a font of
knowledge, I’m hoping someone can help. After many years in storage,
I just unpacked a few pieces of handmade stoneware dishes. One of the
custard cups has a hairline fracture running from the lip all the way
down to the bottom and around to the top again.

Any suggestions on how to stabilize this piece that won’t leave a
bump or discolored line along the fracture?

Thanks for your help -
Linda in central FL
Where it was “zero-zero” visibility this morning…