The Cornerstone of Stars and Flames is a Character Level-Up Material. It is used exclusively with Traveler (Pyro) to level up their talents in place of Weekly Boss Drops.. The Cornerstone of Stars and Flames is a special item used to ascend the Pyro Traveler in Genshin Impact. See how to find this item, where to use it, and the specific locations of the item here!
HoYoWiki - Genshin Impact - The Cornerstone of Stars and Flames: "Heroes ignite the sacred flame, illuminating the world, yet eventually they shall rest, nestled among the stars.""They left behind a stone, a weaving. With these as our foundation, we have erected an everlasting civilization.". The Cornerstone of Stars and Flames material guide for Genshin Impact. Farming locations and usage.