Mineral Identification - Uraninite?

[markfothebeast]

I was thinking of getting a Radon test since we're in "Zone 1", a heavy radon area. I was educating myself on what and where it comes from. It led me to read about Uranium and that's where I saw photos of Uranite and similar minerals. Just then, I remember finding a few odd stones when I excavated the backyard that resemble this black, shiny Uraninite mineral. My curiousity got me here and I'm interested if this may be Urananite or something else. It is very heavy and it shines when washed. I saw another rock with the same mineral on it as well (pictured). The sedimentry rock has a bit of green on it that I typically find 3' - 6' below ground level.

Our bedrock is limestone but the far side of the property it is sandstone. There's a lot of green in the soil as well as strange green rocks that resemble basalt. I'm in the midwest rift zone along the Mississippi. I've become curious about what is in the earth I suppose.

 

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[Clay Diggins]

Uranitite is a mineral, not a rock. Your top pictures are of rocks but the bottom ones do show some mineralization..

I seriously doubt you have Uraninite (Pitchblende) in your area because of your bedrock composition. Uraninite occurs in granitic and syenitic pegmatites, Colloform crusts in high-temperature hydrothermal veins, and in quartz-pebble conglomerates. None of those are related to sandstone or limestone.

Radon levels themselves are usually elevated in areas of granitic bedrock. Generally you won't find many zone 1 areas that don't have granitic bedrock fairly near to the surface. The exception would be the conglomerate beds of Wyoming and Canada. Some conglomerate beds can have higher radon levels due to secondary uranium oxides such as Carnotite or one of it's cousins and even then the Carnotite is not found in "rock" form but as small particles dispersed in the conglomerate.

The bottom rock is probably an iron based concretion from the sandstone. If you do a streak test it will probably show itself, in it's general form, to be Hematite or Magnetite.

Uraninite (Pitchblende) is closely associated with Lead deposits. Lead being the end product of the radioactive decay process it's what Uranium is destined to become in time. If you have sedimentary Lead deposits in your area (Missouri?) you are unlikely to have Uraninite or Radon in any dangerous quantity.

Try the streak test. If you see a gray green streak you might have Uraninite.

 

[markfothebeast]

Thanks for the response. I'm glad to hear from a professional on this subject. We do in fact have what looks like granite to my eyes. I've also dug up plenty of quartz. I have a bunch of large rocks that were excavated when the basement was dug out some 40 years ago. This is in West central Wisconsin by the way. I've been real interested in what types of rock the earth had brought to our area along its evolution. We have mountainous rock formations along the Mississippi known as bluffs that made me curious of its formation.

 

[markfothebeast]

In the first post, the red-ish stone/mineral is not magnet but the first is. Which someone mentioned may be iron or related.