✅ SOLVED Is this missouri obsidian?

[lostandrare]

I put this in a post on hard rock mining and it didn't get alot of love. I found this digging in a fossil bed in jackson county missouri. This was away from water near the top of a hill down an access originally cut for utilities. It has that shine and a smooth texture. I was thinking obsidian at first but that is so rare here. Anyone have an idea?

 

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[unclemac]

is it at all translucent? Overall it looks like a black siliceous stone of which there are many. Think of it as "black jasper."

 

[smokeythecat]

Theoretically Missouri should not have obsidian - no volcanos. It is probably glass slag.

 

[Rhapsody]

Theoretically Missouri should not have obsidian - no volcanos. It is probably glass slag.

Got to agree with smoke it looks like slag glass from a railroad or other industrial waste

 

[lostandrare]

Got to agree with smoke it looks like slag glass from a railroad or other industrial waste

I will have to Google some examples. just don't know how Slag glass get embedded under with bracheopod and bivalve fossils? The brownish material mixed in with the black is what had the fossils in it that made me want to poke around. When I break open rocks of that brownish type the interior is grey with small crystals (calcite?)

 

[lostandrare]

is it at all translucent? Overall it looks like a black siliceous stone of which there are many. Think of it as "black jasper"

I will put it under a bright light later and let you know. I did a quick Google of siliceous stone. It would be in keeping with the underwater creature fossils but that is also associated with volcanic activity in the article I read. I am inclined that way though.

Siliceous rock | Igneous, Sedimentary, Metamorphic | Britannica

Siliceous rock, any of a group of sedimentary rocks that consist largely or almost entirely of silicon dioxide (SiO2), either as quartz or as amorphous silica and cristobalite; included are rocks that have formed as chemical precipitates and excluded are those of detrital or fragmental origin. The

www.britannica.com

 

[lostandrare]

Theoretically Missouri should not have obsidian - no volcanos. It is probably glass slag.

I am inclined after doing some looking at pics and such using the search term "glassy slag" that you are probably right. Just a wierd place for a single piece of it to be found. Nothing similar around the fossil bed. No old railroads in the immediate vicinity.

 

[lostandrare]

is it at all translucent? Overall it looks like a black siliceous stone of which there are many. Think of it as "black jasper."

When I back light it with a flashlight it is translucent on the edges and thinner side. Now I am second guessing my agreement on it being slag since what I am reading says slag is completely opaque.

 

[Older The Better]

Those little pock marks have me leaning slag but there is a black flint here in se ks that could easily be present in mo too. I just took this picture the other day of a frog on a flake of the material. Problem is I’ve never seen the raw material in that melted glassy form it usually comes in little arched pieces with ridges… kinda like fragments of smashed clay pipe.

 

[Rhapsody]

Those little pock marks have me leaning slag but there is a black flint here in se ks that could easily be present in mo too. I just took this picture the other day of a frog on a flake of the material. Problem is I’ve never seen the raw material in that melted glassy form it usually comes in little arched pieces with ridges… kinda like fragments of smashed clay pipe.View attachment 2035325View attachment 2035326

thats a right nice shot

 

[Rhapsody]

I will have to Google some examples. just don't know how Slag glass get embedded under with bracheopod and bivalve fossils? The brownish material mixed in with the black is what had the fossils in it that made me want to poke around. When I break open rocks of that brownish type the interior is grey with small crystals (calcite?)

I certainly maybe wrong just a gut reaction, good luck on the ID its an interesting piece

 

[VickyRenee]

I put this in a post on hard rock mining and it didn't get alot of love. I found this digging in a fossil bed in jackson county missouri. This was away from water near the top of a hill down an access originally cut for utilities. It has that shine and a smooth texture. I was thinking obsidian at first but that is so rare here. Anyone have an idea?

What about that being an agate?