You must mine four rock samples inside The Tombs of Night: A Search For Answers. The rock samples are dropped from wounded scouts in the zone. These are spawned by killing specific named monsters. Once the named monster is dead, simply mine the rock sample that spawns near the scouts body. The scout will always be found near their related named mob.
Lureclaw the Angler: Spawns after killing all the mist grinnins around his spawn at the base of The Forgotten Tears around ( 47, -44, 106 ) /waypoint 47, -44, 106, as well as the rest of the mist grinnins on this level.