Found inside Ne Salas – public dungeon (torch icon). You can reach this area from the west. There is a small dirt road that leads to this place. NPC Cirmo that gives the quest “Passage Denied” is also found in front of the entrance of the public dungeon. Grab it before you enter.
Once you enter the dungeon proceed to the last part of the cave. The collectible is inside northern part of the last room. This is the room with four large metal spikes that come out of the ground. This area is also guarded by Lieutenant Khari. Killing him completes Ne Salas. Shard is hidden behind a stone statue.
Small path from west leads to Ne Salas…
… and its entrance.
Ne Salas entrance map location.
Sand Kingdom Moons - Super Mario Odyssey Power Moons