Black Summoning Stone

Black Summoning Stone is a quest-related tool in Salt. It currently only appears in the quest Path of the Ancients. Using this at night will receive the message "You sense a presence near you."(may be incorrect) and spawn the NPC Varkahn near the player. Varkahn will hold a torch and is close to the player, so it's not too hard to find him.

Source

 * Path of the Ancients
 * Amulet Locations Text