So, first let me quote from page 154 of the Core Rulebook, with the parts I'm confused about in all caps:
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Darkwood: This rare magic wood is as hard as normal wood but very light. Any wooden or mostly wooden item (such as a bow or spear) made from darkwood IS CONSIDERED A MASTERWORK ITEM and weighs only half as much as a normal wooden item of that type. Items not normally made of wood or only partially of wood (such as a battleaxe or a mace) either cannot be made from darkwood or do not gain any special benefit from being made of darkwood. The armor check penalty of a darkwood shield is lessened by 2 compared to an ordinary shield of its type. To determine the price of a darkwood item, use the original weight but add 10 gp per pound TO THE PRICE OF A MASTERWORK VERSION OF THAT ITEM.
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So is a darkwood weapon natively considered masterwork or not, and what is the price of one?
Let's say I want to make a Darkwood Composite Longbow for a +2 Strength modifier. The base price for a composite longbow is 100gp, with an additional 100gp for each bonus. Total 300gp. A longbow weighs 3 pounds. If I want to get the +1 to hit that a Masterwork weapon would normally get, what do I pay? 330gp or 630gp? I would guess that I would still be able to enchant it even if I didn't specifically make it masterwork?
That's kinda what I thought. (Even the part about adaptive.)
So, let me ask this then: Considering that I don't think any primarily wood item is heavier than, say, 8 pounds, is there really any significant reason to make darkwood weapons?
Half-weight spears might well be finesse-able.
Darkwood lamellar armor would be reasonably useful, especially for Druids.
Too be fancy.
My kitsune have darkwood crossbows. And no pants to save on weight.