Shark tooth or just black onyx?

[FireIris]

I’m new so I hope I’m making this right. I found this in north Florida by the St John’s river and can’t tell if it’s just black onyx or a tooth. It’s all equally worn but there’s a slight texture change between parts. When googling black onyx I couldn’t find any that looked similar to compare it to and google didn’t give a clear description of raw black onyx. There’s a slight texture difference between parts and it feels like a normal weight for its small size. It’s sharp at the edges and slightly serrated but I’m not sure if that’s just from ware.

[C2fossils]

Looks like flint to me, aka not a tooth. Keep looking though!

[ClearLake]

Welcome to the forum!  This does not look like a shark tooth to me although I certainly understand why it looks similar to one. I’m not seeing enamel or a root or other features that a shark tooth would have. I also doubt it is onyx as that should exhibit conchoidal fracturing which I do not see. The third picture makes me think it is a broken phosphatic nodule and they are common in Florida. 

[Mahnmut]

Hi and welcome to the forum.

I agree this is not a tooth.

Onyx is a variant of agate https://en.wikipedia.org/wiki/Onyx

The main distinguishing feature I would expect for onyx is banding.

Although Onyx is quite well known by name, its not that common, there are lots of other black minerals.

Obsidian and other volcanic (or industrial, think slag) glasses come to mind.

https://en.wikipedia.org/wiki/Obsidian

In my eyes, the shape of your find fits breaking patterns of amorphous minerals like those mentioned above, not all fractures have to be conchoidal ("Mussel-like").

Best regards,

J

Edited December 9, 2024 by Mahnmut
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