The outer bark of an old mammoth tusk have usually a lot of colours. The tusk soakes up minerals from the ground during thousands of years and stores it in it’s thin surface.
Usually the colour is very thin and there for you have to combine two pieces of mammoth if you want it’s colouring on both sides of the knife. Here is how you do it.
I have used a thin ebony spacer between them to widen the knife handle.