From the town, go through the one that gives you the mission to steal the necklace (towards the widow's house) and continue to the next map, when you enter the next map go left and then go up, in the middle of the Approximately on the map there is a stone with a shining dot, you pick it up and that's it.
Does anyone know where the save files are? my resolution is 3440*1440 and it was automatically set to that, but I missclicked up and now I can't reset the settings nor select any resolution bigger than 1920*1080