✅ SOLVED Looks like a fossil.

[Username1]

My sister found this fossil/rock. Any ideas what this came from? Could it have any value?

 

[Dakota Sioux]

Its most likely a part of pleuroceras genus of ammonite very common

 

[Username1]

Its most likely a part of pleuroceras genus of ammonite very common

Looked that up, I believe you're right. I knew I had seen something similar online. Thanks!

 

[GlowingArtist]

Is that aquatic corral? Doesn',t look like ammonite shell to me, no ridges on sides and doesn,'t have the correct decreasing circumference in it,'s curvilinear shape.

I am going to guess bleached coral. See https://snorkelaroundtheworld.com/2020/10/dead-coral-why-are-they-dying/

 

[Red-Coat]

Is that aquatic corral? Doesn',t look like ammonite shell to me, no ridges on sides and doesn,'t have the correct decreasing circumference in it,'s curvilinear shape.

I am going to guess bleached coral. See https://snorkelaroundtheworld.com/2020/10/dead-coral-why-are-they-dying/

Aquatic coral you say? Are there any corals which are non-aquatic? In any case, it has zero features which could be attributed as characteristic of a coralline structure and ticks all the boxes for the correct identification as a broken portion of the outer whorl from an ammonite fossil.

The whorls furthest from the centre are both the most likely parts to break away from the fossil and the least likely to have the degree of curvature showing them to have come from a spiral.