Not every resource you find in Valheim will have a use, at least not yet. Because the game was released as an early access build, developers Iron Gate Studio are not finished giving everything a purpose. For players looking to find out what the crystals do, they don’t do anything right now. These items are a resource you can find in the Mountains biome.
The crystals drop off of the stone golems. These golems are fearsome, rock-based enemies, and they appear seemingly out of nowhere from the side of a mountain. That’s because these large creatures are resting against the side of cliffs, and unless you notice them quickly enough, you’ll probably walk right into them almost every time. They have a few noticeable features, and if you notice them in time, you’ll see that they have a glittering blue glow around them. Seeing where they are is half the battle, though. Taking them down is another matter.
These large stone behemoths are not going down without a fight. They come in two varieties, one with a spear-like rock in the right hand or where both of their hands are round boulders. You can parry these creature’s attacks, opening them up to a devastating blow. However, we recommend not using any pierce or slashing damage. They take reduced damage from these attacks. You want to stick to using a blunt weapon, such as a mace, to fight them.
After you’ve taken them down, these creatures will drop a small, sliver-like crystal. Right non, in Valheim’s early access build, these crystals do not do anything. You won’t use them for any end-game crafting recipes. But we recommend still holding onto them and hoarding them in a chest for a rainy day. It’s likely these crystals will be used in the future, and when those crafting recipes become available, having an excess amount of these will be pretty nice.