All the rage with ring boxes now are the rustic wooden boxes with initials on them- I think they are pretty tacky- but they are popular- like this:
My husband proposed to me by giving me an old book he got at an antique store- one of my favourite oldies- and he hollowed out the middle so when I opened it, the ring was in there. I was shocked.
By the way, that ring is a beautiful choice and I absolutely love it, she's not going to care what kind of box it comes in. Congrats