My friend found a hamsa hand symbol. What does it mean when she already has one?

My friend and I went out today and when we got back to get her car she just found one lying on the ground at her door, attached to some silver wire. She initially thought it was hers and that it came detached but then saw the wire and that her own hamsa was still on her keychain. Now she has two and has proceeded to wrap the wire around her rearview mirror. I just want to confirm with people more educated on this topic what this means. Is it okay? Is it good luck? We would like to think and hope so but also want to be careful as she already has one. Thankful for any explanations and advice!