Genshin Impact solve the mystery of the stones is part of the Through the Mists quest and the only way to get the Peculiar Pinion gadget.
Speak with Ruu one real-world day after finishing the quest’s first part, and you’ll receive the Pinion with some vague instructions on what to do next. Your first task is to find a Seelie.
Genshin Impact solve the mystery of the stones - Electro Seelie location
Travel to the quest area, but deal with the Rifthounds before doing anything else. They’re persistent and can deal heavy damage if left alone. Touch the Seelie once they’re taken care of. It’s easy to lose track of, but if you do, head further north up the coastline. You’ll see it hovering near a group of Samachurls.
Genshin Impact solve the mystery of the stones - Activate the stones
Follow it again, and it’ll lead you back to the Thunderbird statue. Using the Pinion reveals a set of symbols on the wall. That’s the order you should activate the first set of stones in, so travel to the next quest marker and use an Electro character to activate the stones. Fischl or Sara work best, since they can generate Electro with no cooldown.
The next quest area has its own Thunderbird statue. Use the Pinion again, and activate the stones in the order it shows, going from top to bottom.
You’ll need to track some Seelies down after a few additional scenes play out, but they’re easier to locate. Speak with Sumida once you’ve finished the other requirements to end this quest, and then you’ll have to wait another real-world day for the next part of this world quest to activate.
Fortunately, Genshin Impact still has plenty for you to do. With Peculiar Pinion in hand, you can get some additional treasure by hunting down Star Shaped Gems in the area you unlocked during A Particularly Particular Author. You'll also want to catch up on your Archon quests if you want to take part in the latest event.