Sourcing rare materials from Lost Relics and Ancient Artifacts
Glowing dig spots are the source of Lost Relics and Ancient Artifacts, which only become useful once a Pokémon with the Appraise specialty (like Professor Tangrowth) identifies what you found.
Breaking a glowing block or dig spot with Rock Smash (or another applicable move) can turn up a Lost Relic — a mystery item that's useless until appraised. Small Lost Relics resemble the held items Pokémon carry in the core series and can be framed as wall decor once identified; Large Lost Relics are bigger placeable objects, some of which double as furniture inside a Pokémon's habitat.
Take any relic to a Pokémon with the Appraise specialty — Professor Tangrowth in Withered Wasteland is the reliable early option — and they'll reveal what it actually is. The result is randomized and can turn out to be a habitat recipe, a crafting recipe, or a decorative item, so there's no way to target a specific outcome; it's a volume game where finding more relics means unlocking more recipes over time.
Once identified, relics aren't purely decorative — they can be traded to Gimmighoul or Gholdengo for other rare items, giving you a second use for duplicate or unwanted appraisal results instead of just shelving them. Feeding Mosslax a bitter-flavored dish (a leaf-and-seaweed salad, for instance) is also reported to improve the odds of pulling a rarer item from glowing spots, and running the Dowsing Machine with a Search-specialty Pokémon helps surface more glowing spots to dig in the first place.
Related: Seaweed Salad
Regions: Withered Wasteland
The Mosslax bitter-food rare-item boost and Dowsing Machine detail come from a single source each and aren't independently cross-verified.