Ah, I didn't realize you could discard the necklace. When I met the first goblin, I noticed that I couldn't sell it and just ignored it from then on :D
Hm, that’s strange. You’re supposed to be able to sell it for 3 coins. (You can sell even if shop list is full, as items you sell don’t appear in shop, unlike when you discard them to chest.)
Hmm true, I can sell it. Maybe I just mixed it up with the bag of coins and assumed it applied to the necklace, too, since it looked like a quest item.