Usage of family heirloom/

I found a item called the family heirloom in the cave under route 15. Can anyone tell me what it does/where I give it to someone?

There’s a Hiker who wants an item lost in Route 15 in a nearby town. Try to talk to him to see if its the right one. By the way, would you mind saying which part of the cave you found it in? I couldn’t find it and it would help the wiki document things.

when you enter the cave from the top, there is a formation of three rocks on top of a raised platform. There is a space in between and if you interact with the space, you get the hidden item the family heirloom

Alright. Turns out it was already on the wiki and I didn’t see it.