That second bracelet looks very classic and wearable, and seems to match your sister's style.
It would be a lovely gift!

I'd definately get the second one if it's more your sisters style, it would be such a shame to get something too dainty that she would never wear x

I like the looks of the second one. It looks very wearable and timeless. Is it also a charm bracelet that she could put charms on if she wanted to?

Your idea of something from Tiffany & Co is classy. Both bracelets are beautiful and when she sees the little blue box (especially after so many years of scrimping by to pay for school) she'll be thrilled no matter what is inside so I don't think you can go wrong either way.

The first bracelet definitely has more personality and it looks like it would have better movement/flow. It is elegant but still casual. As for the second bracelet, it might be a safer option but keep in mind that as a student she may have been much more casual and sporty in her style than she might be as a professional. Again, you are not going to go "wrong" either way!

Buying your sister such a beautiful bracelet is a lovely idea!

Personally I'd be a little hesitant to pick one without being absolutely sure that it's a piece she really adores. After all it is a big investment and you want your sister to be thrilled with it.
I know it's not the same kind of 'surprise', but I'd consider going to Tiffany's together and let her make the final decision (it might be a fun shopping outing too;-)
Or is there any way you could find out (through a friend of her e.g.) if there's anything in the shop she really has her heart set on?

Your sister is lucky to have you! I vote for the second one too. I know I have a hard time with bracelets - they have to be the right fit (which I"m sure Tiffany's will accommodate by helping remove links if need be) and style. And I can only wear them on non typiing/writing days since they get in the way when I do these activities. Maybe that's why she's been avoiding them?

I do wonder what is her exact style - and maybe you know that well. Perhaps you let her know that after she's opened the bracelet, you'd be happy to go back to the store with her to help her pick an alternative if this doesn't hit the spot perfectly?

I agree with Inge. Can you let her choose? It is a bit disappointing to receive a gift that you know is expensive but not the one you would pick if you were given the chance.