Sandry thinks Daja's hands are beautiful. She's said so, several times. The way they glimmer in the lamplight, or in the glow from her stone...
Tris thinks about them like scars, because she's got a collection of them of her own - though they cannot be seen. They all do. But that's not how Daja thinks about it, either.
Daja cannot help but remember that her Living Metal came from the unmarked copper of her Trader's staff, and was witness to the second-worst period of her life. (She cannot call it the 'worst' when her parents died weeks before she received the staff.) But the staff was also witness to some of her best.
Briar probably understands it the best. He's got his X tattoos and isn't proud of them, but they're part of who he is, and what he once did.