Does anyone know where I can find some in chapter 2?

eh

If you need it for crafting, then I'm affraid you need to buy it. It's, iirc, spawned randomly in containers once, but you probably checked the whole area you had. Go hunt monsters to get their parts and sell them.

Check the Mysterious Merchant outside the Inn, if you are on Iorveth's path.

Yeah, it was to save some coin on Harpy traps; I had bought two ore from the blacksmith, the mysterious merchant had none. I just went back to the smith and he had four more that i needed. I didn't think they would respawn that fast.