Genshin Impact : Marked Shell

To obtain Marked Shells you'll need to find and destroy Consecrated Beasts at level 60 or higher. The higher the level of the Consecrated Beasts you destroy, the more items they will drop. You can also trade in Starglitter for Marked Shells. It costs two Starglitter for one Marked Shell on the Starglitter exchange. Consecrated Beasts can be found around the Desert of Hadramaveth. Refer to the images below for exact locations: