Well you should gift your sister the best form of jewelery.You should gift her white pearl necklace as she likes simple one.
I got her DY pearl necklace for her 25th. She loved it!!! I was in Tiffany's this weekend and absolutely love elsa peretti diamonds by the yard necklace. http://www.tiffany.com/Shopping/Ite...1323351+101323340+101424821-x+-n+6-ri+-ni+0-t+