What is this

[Letichias]

 

Amazon Forum Fav 👍

Agony and Death on a Gold Rush Steamer: The Disastrous Sinking of the Side-Wheeler Yankee Blade - Grab it through Amazon!

[detectorbishop]

It's hard to know, a bit more information would help. could you take a picture next to something to show us some scale. where did you find it? is it heavy or light. that sort of thing. thanks!

 

[CRUSADER]

a natural rock

 

[AKSasquatch]

Doesn't look to be anything special. I would guess a rock of volcanic origin with the small bubbles/inclusions. Then colored buy iron staining.