I have used quite a bit, mostly mammoth ivory, but have used elephant ivory as well.It cuts like stag antlers, use a finer tooth blade for cutting it.The main thing with ivory as other natural products is not to get too hot when working it as you can induce cracks and warping.If your power sanding always use fresh belts and keep your speed down.If drilling always have a wood backer to prevent blowout.When using as knife scales, especially when you want to keep the color and texture showing always sand the backside only, sanding the front side too much will remove color, so keep sanding there to a minimum.I usually take the sanding down to 600 grit or finer, for real nice go to 1000-1500 grit, before buffing.I buff with a power buffer, soft flannel wheel with white rouge and again go lightly and don't bulid heat.
Real elephant ivory is not hard to find, there is a dealer just North of me, but it can get pricey.Dave
These are two knives I recently finished and while I know they are not what the mods want to see in here, they do show uses of ivory on knives.
This one features Fossil Walrus Ivory handle and a Mammoth ivory inlay on the sheath
This one has Mammoth ivory scales and inlay on sheath