It is the official badge of the explorer society.
||Grynch Clan Goblin, Hellhound
||Mortimer (Northport) 50 gp
Angus (Port Hope) 50 gp
||Looks the same as the Elven Brooch.
In the Santa Event, it was also dropped by Grynch Clan Goblins.
<spoiler>Item obtained in the Explorer Brooch Quest.</spoiler>