So I have this piece of Lignum Vitae

[ovenpaa]

This was given to me recently and I would have thought it was Lignum Vitae, it certainly looks, smells, feels and weighs like it should be, however I have never seen it split and shake like this before. I wetted the surface to show the colour, otherwise it just looks very old and dusty and has certainly been hanging around for a while since the tree was felled.

Thoughts anyone?