Hi. Does anyone know what this is?

[Deedee67]

 

[Johnho]

That's an odd one. The light mineral on the inside looks like Quartz. that black stuff is odd. Can you scratch it off with a knife? It just doesn't look like a natural coating from the picture.

 

[Odanscoils]

Interesting.
Wondering what it would look like with a laser beam hitting it.
I do that looking for rocks on the beach along with my UV spot light.

 

[tab-nabit]

Interesting.
Wondering what it would look like with a laser beam hitting it.
I do that looking for rocks on the beach along with my UV spot light.

Well that right there in interesting too.

 

[Larry (IL)]

You have a beauty......... black quartz. https://trulyexperiences.com/blog/black-quartz/#Physical Properties of Black Quartz

 

[Johnho]

Does no look like black quartz to me. It appears to be some sort of coating. That's why I asked for them to scratch it.

 

[Odanscoils]

Looks like quartz and hematite.

 

[north1]

Could it be an agate. They usually have a cortex/rind.

 

[Geologyhound]

I would definitely subject the clear portion to a scratch test with a knife blade. If it can be scratched with a pocket knife blade it is not quartz. It just looks a little too rounded to be quartz to me. (If the quartz is that rounded, then any softer host rock should’ve been worn away.) If it can be scratched with a knife blade, my guess would be zeolite. The host rock could then be basalt. If it cannot be scratched with a knife blade, then it probably is quartz. Do you mind saying the general region where you obtained it?

 

[sprchng]

Pebble from a pot hole repair job

 

[Johnho]

I think that solves the question, it's a tar or asphalt of some type. The quartz, I'm pretty sure, was part of the mix.