Salaam All ~ The use of high density modern composites on hilts. 
To save the Rhino, Elephant and other endangered species here are a few alternative Omani Hilts that are very capable,  properly weighted and take all the usual silver pin decoration just like horn and bone. 
Oddly I have never seen Mamoth tusk used on Omani Khanjars.  
 
 
Regards,
Ibrahiim al Balooshi.