That sucks. You have every right to confront her about it, and let her know in no uncertain terms that this was unacceptable, you're extremely disappointed, this was NOT her property to give away. I would also rather not have that person in my life anymore. There's not much else you can do now, it's gone. I wouldn't bother going to the trouble of getting her prosecuted. What's done is done, but in my opinion you should make it extremely clear to this thieving scumbag that you're shocked and saddened -- basically convey the same things to her directly that you've posted here. You have a right to feel betrayed and surprised that a trusted person would do this without asking.
The same thing happened to me on a larger scale. Members of my family stole all my stuff and then made sure I could never contact them again. This was my older sister, and her grownup kids. I had musical instruments, all my vinyl albums collected from a young age including rarities, my books, etc, they got everything and when I tried to ask about it that's when the sh"t hit the fan. My own blood did that to me, thieving jerks.