Oosik is too porous and would require filling with epoxy and bubbles turn it into a nightmare unless done wonder pressure.
Rams horn is hollow and will likewise give you fits. Most horn is boiled and run through a press to make it shorter and thicker while getting rid of the hollow. They can literally make it any length and width and height they want, given the volume of horn. A PITA to just wing it.
Ivory dyed black is pretty good looking.
There are a lot of woods that should be avoided just because they are too soft. I have used burly redwood on a few tips on ultralight hunting rifles... The redwood does not resist damage the way a fore end tip is supposed to. But it is pretty.
Get someone with good critical color sense... women see color better than men... to look at it to see if it clashes. Some woods look good but do not look good together.
