The white parts are definitely bone, one can clearly see the haversian canals...
Some types of old plastic will ignite in an seriously explosive manner if you set a hot needle in them... Some wont even melt...
And many materials will always bear the mark of a test that proves nothing usually...
Seeing if something smells when it burns is a bizarre test, that collectors shouldn't realy be using...
Your eyes can tall you more than trying to burn an antique will. :eek
spiral :