Gathering brings in the raw goods. Refining makes the common materials from them, and refining a common one again with an additive makes the uncommon ones. Production takes them from there.
Uncommon metal, refined from Iron Ingot with Nickel Ore and Tungsten Ore by Smelting at level 30 (recipe).
One Meteoric Iron Ingot takes 8 Iron Ore, 1 Nickel Ore, 1 Tungsten Ore, and 4 Chunk of Coal.
Refined further into:
Production takes it, or its forms, in 62 Blacksmithing, 2 Alchemy, and 2 Carpentry recipes.
What it adds to gear parts made from it: