Mostly, you will find it scattered across Yashiori Island in the middle of the region, and you’ll need more than a few pieces to power up two recently introducing charcters.
Genshin Impact Crystal Marrow - Where to find Crystal Marrow
Like other ore items scattered across Teyvat, Crystal Marrow tends to sprout up around rocky outcrops. Most of the locations are around the center of Yashiori Island and the cliffs branching out from it, but there’s also a collection of Crystal Marrow west of the Kujou Encampment area on Kannazuka.
Crystal Marrow Locations - Yashiori Island
Make sure to steer clear of lightning strikes while hunting Marrow on Yashiori.
Crystal Marrow Locations | Kannazuka Island
Genshin Impact Crystal Marrow - Crystal Marrow farm
Also like other ore items, Crystal Marrow takes a couple of real-world days to respawn. There’s no way to generate your own ore yet, so you’ll have to wait for the refresh to gather more. You’re primarily using it for just one thing, though, so there’s no great demand for huge batches of it at first.
Genshin Impact Crystal Marrow - What is Crystal Marrow for
Sayu uses Crystal Marrow in all stages of her level-up Ascension. Later phases require 40-60 chunks of Crystal Marrow, so you won’t be taking Sayu from 0 to level 90 in one day. If you end up with a surplus of Crystal Marrow, there is one other use for it. Some of Inazuma’s world quests require a dozen or more pieces from you. Speak with Chouji near Jakotsu Mine to start his quest chain, then follow up with him later to unlock one of Inazuma’s secret achievements. As well, the PlayStation crossover character Aloy needs Crystal Marrow to Ascend, and she’s sure to be popular. Future characters also might use Crystal Marrow, so it’s worth hanging onto some for a while if your inventory isn’t full. If you’re lucky enough to get Yoimiya from the latest Genshin Impact banner as well, make sure to stock up on Naku Weed from Narukami Island and elsewhere. She’ll need plenty of it for her Ascension.