IT LOOKS LIKE A GOOD OLD ONE TO ME I WOULD GUESS IBAN BUT THEN I AM FAR FROM AN EXPERT. THE HANDLE IS DRIED OUT AND PERHAPS SUN BLEACHED FROM A LONG PERIOD OF STORAGE. BONE AND ANTLER BOTH OXIDIZE AND FORM A WHITE CHALKY COAT LIKE YOUR EXAMPLE'S HANDLE APPEARS TO HAVE. IT SHOULD CLEAN UP NICELY WITH JUST A LIGHT CLEANING AND OILING OR WAXING UP. THE BLADE , HANDLE AND SCABBARD MAY HAVE BEEN REPLACED OVER THE LIFE OF THE MANDAU OR ALL ORIGINAL. ON THIS PARTICULAR SWORD I WOULD GUESS ALL THE WORK WAS DONE BY THE DAYAK OWNER AND NOT JUST FIXED UP TO SELL. I LIKE THESE OLD ORIGINAL ITEMS THAT HAVE NOT BEEN TAMPERED WITH OUTSIDE OF THE CULTURE THAT CREATED THEM.
