Is it okay to remove valuable items from a friends house without permission?

I just moved into my home and had a small housewarming over the weekend. I gave a one-time tour to the guests. This way I could keep people from wandering upstairs without me.

I noticed today that on Snapchat my friends was wearing one of my diamond necklaces. I was furious 🤬😡🤯.

She dropped off the necklace and matching earrings a while ago. She said I’m overreacting because it’s not like she stole anything. That she planned on giving me my stuff this weekend.

Friend or not I believe she’s a thief. We are no longer friends. I let her into my home and she went through my jewelry box and concealed my property and left with it! I can’t trust her anymore.

Am I overreacting?