Where can I find some adamantite, I need it for a weapon upgrade.

the evil leader of the zoo in blacklake rich people area
as well as the orc in the bladelake district poor people area tower

you might want to hang on to them, I couldn't find any in chapter 2.

there is none in chap 2 or 3 dont know about 4 yet. so far that means there is 2 peices available. 3 ironwoods, unlimited fairy dust(chap 3), unlimited gargoyle skulls(chap 2), bout 4 dragon bloods so far,1 special holy water,2 diamonds in chap 1, but alot in chap 3 and 4.

which district(s) did you find the diamonds at in chapter 1?

Diamond Spoilers:

The first and easiest to get is in the Docks under the building where the auction is taking place. The second diamond you have to earn, the winch that runs the brothel in the main town has it, after you retrieve the 3 items she wants she will reward you but you have to pursuade her to get the diamond from her. You might be able to kill her for it but I can't say I've tried that.