Corrosion on gilded keris blade

[A. G. Maisey]

I think it is probably fire gilded, but this is an opinion based on a photo that has been viewed on a screen. Don't quote me.

I would call it lung-lungan = vines, maybe it has other names also.

I do not know when gold was first used on keris.

My opinion as to the reason for its use is that it would have been used as a hierarchical marker. Certainly not for any talismanic reason.