I have a character A whose friend B has just come home from travelling abroad, and as A is stressed out B gives him a protection charm. I know what it is, I just don't know the name of it! I saw them in Finland, specifically in the north in Suomi/Sami territory, and possibly in northern Norway as well. They were half-palm sized silver balls with quite intricate patterns on them, usually on a chain. I believe some had small metal pellets in them to make them chime, and they were possibly something to do with the aurora borealis, and possibly aimed originally at children (like, versions being hung above children's beds) but I might be mixing up different charms.
I've tried googling various phrases along the lines of "suomi protection charm" "finland protection charm" "protection charm aurora borealis" but I think this is the kind of thing that people are more inclined to know about themselves, rather than being able to find!