I think that the best option is giving girl a beautiful ring or bracelet. It will "tell" her that she means something to you, and that you have feelings. You can also choose a piece of jewelry with colored stone, for example, pink, because it looks beautiful. What is more, you can send it to the examination first and give her also colored stone certification, where will be the info about shape, measurements, color, or other characteristics. As for me, such a present is exciting and meaningful.