Giving a gift to someone, especially to someone you love, has got to be special. The best way to make a gift special is to personalize it. There are fewer gifting options that are more personal than personalized jewelry. And we're not talking simple inscribed jewelry, we're talking about going one step further.
Have a gorgeous brooch made to order, or if you can manage it, hunt for an original brooch with her birthstone in it. If not an antique, then get a modern one made with a 'secret compartment'. In the 'secret compartment' you can have a tiny photo of her and you placed.
Whatever it is, get the different charms encrusted with the birthstones and fasten them onto a pretty, plain bracelet. It will look beautiful, plus it will have a special place in their heart.