Copper Bar

Everything made from this is temporary by design. Its job is to get you a pickaxe that reaches the next ore tier and a blade that survives the first night. After that the bars become crafting filler for furniture, a couple of early staves and the odd station, which is still a reason not to sell the whole stack.

Worlds generate one or the other, and tin is quietly the better roll. The wrinkle is your starting gear: every new character spawns holding copper tools regardless of which ore the world actually contains. In a tin world that means the Copper Pickaxe in your hand is worse than the one you could craft, so mining a few Tin Bars early is a real upgrade rather than a sidegrade.

Hang on to a partial stack. Copper stays in enough recipes past its useful life, including the Amethyst Staff and a pile of furniture, that a small reserve saves you a trip back down to the first cave you ever dug.