I have to agree with Nechesh. Whalebone is somewhat prized, but the fragility is what I would question. I have seen one kampilan done in whalebone. Amazing, but parts did not seem to hold up as well as others. Fossil elephant ivory is also a problem - talismanic, but very fragile and thus have only seen 3 Moro examples, one of which I own.
I have also been eyeing this keris and was wondering about it. Personally I love John's better, this is a nice one too.