The material reminds me of a mirror frame we had from Morocco inlaid with.. camel bone.   
No indications of ivory at all imho.  
No schreger lines and the yellow colour would indicate a long storage in the dark in case of ivory, but even than ivory does not tend to become this yellow almost orange. 
 
I go for the camel bone.
		 
		
		
		
		
		
		
		
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