I agree, it's most likely Whale bone.
We find old Pilot whale (Blackfish) bones in the salt marsh we live on the edge of. These bones have lots of 'pores' visible.
Pilot whales strand on the barrier beach during the Fall and used to wash over into the marsh after storms; now the town comes out with a bulldozer and buries them.
Kino has a kampilan with a whale bone handle and guard.
http://www.vikingsword.com/vb/showth...+bone+kampilan