Hi Lotfy,
Thank you for sharing your new piece - may you enjoy it in good health!
I am as sure as I possibly can be, without having it in hand, that your hilt is made from bovine horn. In a longitudinal section, rhinoceros horn will not display the hazy "streaks" that are visible on the side of yours, but rather be of a type either where the grain has a look of crushed/slushed ice or where the individual chitinous fibres are visible - the latter looks exactly like a bundle of hard compressed hairs (which it is

).
Rhino as well as bovine horn
can be translucent as well as display a wide palette of colors, so these can't be taken as a proof characters on their own.
I attach here for comparison a picture of the hilts of a couple of rhino-nimchas that recently passed through my hands. The icy type is on top - the hairy on bottom. The picture kindof sucks, but the swords aren't here anymore, so new pics are unfortunately not possible. I hope you will see what I mean though.
Personally, I think people often overestimate the aesthetical qualities of rhinoceros horn, just because it is rare. I've often seen somebody gawk over a piece of rhino which, in all honesty, was as gray and dull as concrete. Conversely, I recently saw the handle of a bade-bade and the belt clip of a Javanese knife, both made in qualities and colors of buffalo horn, that nearly knocked my socks off!
In my opinion, when concerning
any horn, beauty is all about grain, color and of course age patina. The source species is less important.
Cordially, - Thor