Woolly Mammoth Ivory! Is it Always White in Color?

Good question! Woolly mammoth ivory is not always white. It can range from bright brilliant white to dark chocolatey brown, with all shades of caramel in between. Woolly mammoth ivory can even be, wait for it…. blue!

Me posing with “Blue Barbie”. A tusk recovered 2020 at The Boneyard.

So what causes the different colors?

A little mineral absorption plus a key ingredient, time! The woolly mammoth ivory we find at the Boneyard has been buried in the ice and muck for tens of thousands of years. Over time, the minerals and colors in the icy mud are absorbed by the ivory, changing its color to the colors of the mud and minerals it's buried in. Typically, the tusks we find have a dark exterior and a white interior. Minerals are more easily absorbed by the closest material to it. Therefore, the center of the tusk remains white because the minerals are not in direct contact with it. So why the blue?

Multiple tusks displaying the ancient ivory color pallet.

You are probably already aware that various minerals oxidize to different colors. Iron oxidizes to red, think a rusty nail. Copper oxidizes to blue or green, Statue of Liberty ring a bell? Vivianite is a crystal resulting from the presence of hydrous iron phosphate. When this mineral forms, crystals grow. These crystals are called vivianite.

Close up of vivianite crystals on a woolly mammoth tusk.

Vivianite starts out colorless but can turn to many shades of blue, green, black or even purple as it is exposed to light. The more light the vivanite is exposed to, the darker and richer the color becomes. Not only do woolly mammoth tusks absorb minerals and grow vivianite crystals, many other ice age bones do as well. Check out the woolly mammoth molar we recovered, completely encased in vivianite.

When we hunt for ice age remains at The Boneyard we keep our eyes out for any blue color that might emerge. If we see blue, we know we’ve found an ice age specimen.