Board Thread:Show-Related Questions and Answers/@comment-24304025-20140715163532/@comment-4975807-20140715173218

He took the necklace as payment because he disliked that Snow bothered him about a deal that never happened (Charming's fake deal with Rumplestiltskin, which he told Snow he had done). As a warning, perhaps, he took the necklace to show Snow that he was seriously annoyed, lol.