Gold Pickaxe

Meteorite is the reason to craft it. The early pickaxes bounce off the ore and leave you staring at a crash site you cannot touch, and this tier clears it. Bring an Obsidian Skull before you start: the ore burns you on contact and mining a full deposit without one costs more health than the trip returns.

If your world rolled the other ore, the Platinum Pickaxe is a little better across the board, but the gap is small and both reach the same ore tiers. Use whichever your world gave you and spend the trading effort on something that actually changes what you can mine.

Light if you only ever dig with it, Legendary if you expect to fight with it in hand while tunneling. Most players want Light, since by the time you are swinging a pickaxe at enemies you have a real weapon anyway.