Originally posted by M.Red:

the knife made from chitin is equal to iron age weapons imho

ah, I haven't run into chitin yet, but then, judging from the wiki, you probably need a bit more than the basic raft to get it, and I haven't unlocked anything better so far (first time I've reached iron so I don't know what happens).
But chitin is something you can get about the time you reach iron?