My husband made my ring out of a piece of wire. I wore it with pride but looked like an idiot for months. I thought it was romantic and my friends weren't any less jealous.....It was truly the thought that counted.
I still have it and carry it in my purse everwhere I go. The engagement ring was too cute.
We picked matching wedding bands together thank god, because I thought his personal choices were too flashy and were no indication of our non-flashy relationship and lifestyle. See how I am? I'll wear a wire but refuse to be flashy...I am non-traditional.
If she is traditional I might go with a band of some sort.
Ask her parents advice as well, they may have a good idea and they will be happy that their opinion was noted. What if she told her mom what she wants?
Not only should they (the parents) know about it, did you ask their permission first? Not that their answer really matters, it's just in good form.....