Lathas' amulet is a now-discontinued quest item from the Plague City quest series. It was given out as part of the reward for the Biohazard quest in RuneScape Classic. Players were given the amulet by Lathas so that he could inform them upon the discovery of a way into the forests of Isafdar; similar to how Lathas' Messenger appears for Regicide. The amulet's gem was green until the release of Underground Pass, when it changed red. To begin the quest, player needed to visit King Lathas.
This amulet is identical to the female versions of the Armadyl pendant and Pendant of Lucien as they all have a red gem. However, the male version, unlike the other two identical amulets, has a red gem. Because of this, you can truly tell if someone is wearing a Lathas' amulet if they are male and are wearing said amulet.