Sonoma Coast Fossil (?)

[jsch]

Hi! Sorry for the low-quality photos. Not sure if this a rock or fossil. It has an almost honeycomb pattern on the inside. Found at the beach on the Sonoma Coast in Northern California. Thank you for taking a look at it. 

Edited February 14, 2021 by jsch

[DPS Ammonite]

What beach? It looks rather hard; possibly Monterey chert.

[IsaacTheFossilMan]

Could you give us more specific information? (if possible) I'm personally not seeing anything organic, but I could be mistaken.

[HuckMucus]

I think it's a fossil that has spent a lot of time rolling around in the sea.  The inside looks like the inside of bones I've seen, only worn considerably.  The fact only one end is open reminds me of a tusk tip but I don't know what they look like inside.  I'm looking forward to the comments.  

 

Edited to add:

 

The grey looks like granite.  The sides almost look like petrified wood.  My imagination sees "work".  The third photo, about a third of the way up from the bottom, just right of center, I see circles.  I also see "images".  But I'm a'feared it's like seeing stuff in the clouds.  LOL!

 

The bottom photo, inside-right shows like honey comb.

 

I thought of one of those things for holding the end of a fire drill but the inside is not round enough.  Nevertheless, I get a tool vibe.

 

I'd like to see shots of the edges.  Especially the edge with the notch toward the top.

[Thecosmilia Trichitoma]

I agree with it not being a fossil.

[val horn]

The shape is certainly suggestive but I do not see enamel or bone, nor is the internal pattern something I would expect in a bone or tooth. It is possibly an external mold and I would love to put dental impression material inside to look at it.

[Sagebrush Steve]

The Sonoma Coast is mostly Franciscan complex metamorphic rock, few fossils.  It looks somewhat like the tafoni found in Salt Point State Park but I have never seen one quite like that.  I agree it’s probably geologic but it is a very interesting piece.