🔎 UNIDENTIFIED Black rock from Iowa creek

[Blackfoot58]

This is a micro/cryptocrystalline black rock. I cannot scratch it with a steel knife blade or nail. The polish was done in the creek naturally. It doesn’t check out as hematite, basalt or biotite. It is 3 inches long.
I’m wondering about basanite jasper.
I don’t want to break it to see how it fractures, but would like to see what it is. I don’t see black chert often. There is some dark brown chert that can appear black, but this is jet black. Any thoughts?

 

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[Terry Soloman]

Obsidianite

 

[Blackfoot58]

Obsidianite

I understand that obsidianite is man made from volcanic ash. This rock was found in a remote area, and sifted from the creek. I can’t see it being man made.

 

[Terry Soloman]

Apache Tear

 

[Blackfoot58]

Apache Tear

No volcanoes in Iowa. Maybe it was traded for at one time. ?

 

[fuss]

It looks like the weathered Basalt I have found here in Wisconsin from the photo. Black Chert is a second possibility but you should be able to tell the two apart pretty easily by looking close with a 10x loupe if you have one. Try a streak test as well.