🔎 UNIDENTIFIED Obsidian Look-Alike?

[Blackfoot58]

Creek walking today in SE Iowa.
Found this black, glassy rock. I’m told there was no volcanic activity in this area, so no obsidian.
I’ve found a lot of black, shiny rocks over the years, but none like this one.
It doesn’t resemble any of the various coal samples I’ve found either. Ideas welcomed. 👍🏼

 

[Bucket Lister]

Am I seeing tiny bubbles?

 

[CreekSide]

Am I seeing tiny bubbles?

I can’t tell if it’s bubbles or cortex. Adena culture will leave some cortex on their hand held artifacts.