mandaublade laminated? local melted ore?

[Mytribalworld]

On one of my mandau's the blade on some places shows a pamorlike structure.I didn't see at others that and don't know how to call it.
Maybe anyone of you have a mandau with this structure/lamination?
The mandau is north borneo style (probably Dusun)
very nice carved scabbard with silver bands.

happy newyear!!

Arjan.

( will list some nice tribal art next week on ebay)