What is this egg-shaped object?

[corvus corax]

I found this on the shore of Lake Almanor in Northern California. It's a human-made lake created by the damming of the Feather River about a century ago, and is near Lassen Volcanic National Park. It's very symmetrical and pretty heavy for its size. You can spin it like a top on its major axis. Pretty smooth, non-porous surface. Is it a concretion of some kind? Fossilized bird egg? Artifact of the Northern Maidu tribe that lived in this area? I need your help solving this mystery! Have looked at thousands of pics, but nothing looks quite like it.

 

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[DCMatt]

Looks like a darning stone to me.

You know the old saying... "Sometimes I get a hole in my sock. Darn it!"

 

[GaRebel1861]

Looks like a darn stone to me as well.

 

[Charlie P. (NY)]

Stone eggs were a thing. Not just for darning socks but as knick-knacks for good luck.

They also can be put in nest boxes to encourage chickens to lay in that spot. We use gold balls for that.

 

[Tony in SC]

Could be just a rock?

 

[Georgivs]

I'm leaning towards a nest egg too, of course things like this could have multiple uses. I found a blown glass nest egg recently.

 

[Garscale]

I have seen polished granite nest eggs before. That may be what you have. Super cool.

 

[galenrog]

The two most likely answers are “darning stone” and “nesting stone”. When my grandmother had chickens, and we traded eggs for milk, darning stones were used as nesting stones.

They both were made in various sizes, were readily traded by those who made them, traveled with many migrations, and can be found in many cultures. All are generally egg shaped.

Time for more coffee.

edit: Additionally, a common skill with lapidaries is the making of stone eggs.

 

[antmike915]

Pretty cool, I would've picked it up as well.