semi-dual edged badik?

[kai]

Hello Moshah,

if the blade was made with such besi with higher carbon contain, does it mean it can easily break?

I wouldn't worry (unless one tries to abuse it as a sharpened pry bar); competent differential hardening can go a long way. If used incorrectly, the weak point (for most of the personal sidearms throughout the archipelago) would most likely be the hilt IMVHO.

I've read somewhere stated that besi melela was actually comes from a sandy grains along the west coast of java. Is that true?

I'm sure there were a lot of local sources; secondary iron deposits are not rare in wet climates.

if not laminated, means that it was not done like how a keris should be?

These are laminated (on a microscopic level) and traditional. There may be some blades made from imported European steel hiding within the wesi/besi malela category but usually you will see some forging lines suggesting extensive local forge work regardless of the primary source.

Regards,
Kai