Good Luck Charm is part of the Better Late Than Never quest chain. This quest chain starts with 
It would seem that I was wrong about you <name>, and for that I owe you an apology. My sister sent me a number of personal effects, including humorously enough the deed to the Felstone farm. I think I'll pass on reclaiming it right now.
If my sister's spirit remains tethered to the farm and cannot rest, please... could you return this to her? It is half of a good luck charm she had, with her husband having the other half.
Maybe her knowing I have these things will now put her soul to rest.
John, sweetheart... is that you? I'm so cold all the sudden...
You give the half-charm back to the apparition. She looks at it, then at you expectantly.
"Honey, where did you put your half of the charm? We can't be together unless we have both halves. Honey... can you see me?"
Upon completion of this quest you will gain: