Defeating the first Valheim boss Eikthyr is key to crafting a pickaxe - those antlers sure look like they may be turned into a handy tool… Just because this is the first boss doesn't mean its easy ...
Iron Gate Studio's Valheim has a heavy emphasis on resource gathering, and there are times when it can be incredibly time-consuming, especially early in the game when one's tools aren't up to scratch.
Crystal shards only drop from stone golems. You’ll find these in the Mountain biome, but it might take a bit of searching. Stone golems only react when threatened, so you’ll need to investigate ...