Xasterix, the Maguindanao pommel looks like aged Mother-of-Pearl in silver frames to me. I have seen it darken like this.   
 
The other pommels are ivory.  The red coloration is the result of the presence of sulfur which oxidizes the ivory from red to a dark reddish brown or a honey-is brown.  
 
I find the T'boli bells interesting.
		 
		
		
		
		
		
		
		
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