My friend lost my $600 earrings and ipod?

I dont know if she stole or lost them, but shes my best friend and a few months ago she begged for me to let me let her borrow my $600 dollar earrings. I told her she can, but has to give them back to me. So after a few weeks later, my mom was asking for me to wear them but I had to give her an excuse because my friend had them. Now, a few months later (I know, I forgot about them) she told me that they where in one of her purses, and we both searched every purse she had and they werent in any of them. My mom has been freaking out over them because Ive had them since I was a baby. So today I brought them up again and she said "My mom even remembers me giving back to you," and i know for a fact she never did because I would of found it by now. And also, we started bringing ipods to school and she always kept them in her bag and brung them home with her. She lost both of them, I ended up finding hers in the "bag search" but now mine is missing. She says shes 100% sure she doesnt have either and now im really f**cked. what do I do? How do I find them at her house? Shes also my best friend and I cant start any problems with her. I know she wouldnt steal them but she always wants to borrow my brand name clothes and I never want to give them to her because im scared she loses or damages them. I cant let her repay for my earrings and ipod so.......