knife for id please
 

What origin is this knife, ottoman?
It measures 46cm long, 33cm blade, the grip is marine ivory.
the scabbard is in silver inlaid coral

Yes, you have there a very nice Ottoman "court dagger" with what appears to be a walrus ivory hilt.

The blade is likely some form of wootz, likely low contrast or perhaps sham. It may need to be carefully etched. That said, there is also the possibility that it is not wootz, but so many of these are, and as nicely as yours is mounted I am betting it is.

ottoman dagger
 

yes ottoman lovely example made my day thanks for sharing it :)

Based on round unstriated corals, I would think of Bosnian Foca manufacture.
Locally called Bodezh.