I made no comment about yours nice looking knives Jen,

Just about ivory in general.
I can see the one on the top of the left one is probably Elephant, I cant see enough detail of one on the right to be sure but I think your probably correct. I couldnt be certan from those pix, so I passed no comment.
The end grain should show intersecting diagonaly curved lines under a lens if Elephant or mammoth.
And changing stripes of refraced light on the long gain if turned fore & aft in sunlight.
cheers,
Spiral