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 wood, refined from Pine Timber with Pine Resin by Milling at level 20 (recipe).
One Grey Pine Timber takes 12 Pine Wood, 1 Pine Resin, and 8 Creosote.
Refined further into:
Production takes it, or its forms, in 235 Carpentry and 4 Tailoring recipes.
What it adds to gear parts made from it: