When you find Momosik Shrine, northeast of the Death Mountain peak, a beam of light points to the shrine's crystal.
Quest Location
This quest can be begun at Momosik Shrine, northeast of the peak of Death Mountain.
How to Complete the Quest
Enter Death Mountain East Tunnel and use a mine cart to reach the Igneo Talus at the end of the rail. Defeat the Igneo Talus to get the crystal, then attach the crystal to a mine cart and ride the cart back out of the cave. Take the crystal to Momosik Shrine to complete the quest.