Obsidian Valheim 1.0.20
Obsidian is a natural resource found in the Mountains of Valheim. It is used to craft Frost Arrow and build Tool Shelf.
“Dark volcanic glass.”
Obsidian is a Material described in the game as "Dark volcanic glass." It first becomes available in the Mountains. Each piece weighs 2, and you can carry up to 50 in a single stack. It can be teleported.
Obsidian is used as an ingredient in three arrows: Frost Arrow, Obsidian Arrow and Poison Arrow. It is also needed to build the Tool Shelf.
Found in the world
It is placed in the world by the world generator: see where to find Obsidian.
Used to craft
Frost Arrow, 
Obsidian Arrow, 
Poison Arrow.
Used to build
Other material items
Acorns, 
Amber, 
Amber Pearl, 
Ancient Bark, 
Ancient Coin, 
Ancient Metal, 
Ashlands Gourmet Bowl, 
Ashwood, 
Asksvin Bladder, 
Asksvin Hide, 
Asksvin Neck, 
Asksvin Pelvis.