As I remember Emer is the village near desert. Just go around that area, when you hear the sound, then go to the camp scene. You will find an element item somewhere in the camp scene.
For more details:
Having found the first gem, and the horn of stars, we have to possibility to go find the second gem. When hovering over the horn you will see a hint of where to find the second gem.
so go camp near Emer at night. Walk around in the camp, when you hear a horn blow go look for a yellow flare. Then you will get a gem when you walk through it.