Rock-shell chunk

Rock-shell chunks are dropped by Giant Rock Crabs and King Sand Crabs. These are used to make rock-shell helms by giving the Skulgrimen 1 dagannoth hide, 5,000 coins, and 1 rock-shell chunk.

Giant rock crabs are found in the Waterbirth Island Dungeon, while King Sand Crabs are located within the south-eastern section of the Catacombs of Kourend. Players may find King Sand Crabs more favourable to kill for rock-shell parts, due to the lower melee defence; it should be noted, however, that Giant Rock Crabs have a -10 Magic defence bonus, which makes magic more effective on them.