Please help me ID this rock.. Silver? Pyrite?

[redvictor1]

I found these rocks near bedrock at an old load gold mine recently. I have never seen anything like it before. Colors vary from rust to almost black (burnt looking), and the rock is full of round oval air pockets. Some areas appear grey with silver metal looking streaks. Here are some photos I took as I broke up one of the rocks. Any help with identification would be great! Should I send to the assayers?

Thanks!

 

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[AU Seeker]

My 2 cents is that since you found them near an old lode mine that they're slag that was produced when they smelted the gold ore to reduce the impurities and then pour dore bars that would eventually be sent to the refinery for further refining.

It's possible that there could be some gold and or silver left in the slag, that could posibly be recovered by crushing and resmelting the slag

 

[smokeythecat]

AU seeker is correct, it's what's left after the metals were smelted out of the ore.

 

[redvictor1]

What chemicals do you think they used to do the smelting? Is this stuff dangerous to handle now?
Thanks.

 

[AU Seeker]

What chemicals do you think they used to do the smelting? Is this stuff dangerous to handle now?
Thanks.

It shouldn't be a problem handling the slag, usually borax and silica/sand was used to smelted the ore.

 

[Tod Ringam]

redvictor1 I'm quite sure this Iron Gossan,( iron oxide). Tod R.

 

[AU Seeker]

I agree that it could also be gossan, but even though some gossan has the air bubbles present as in his photos, most gossan does not.

 

[BosnMate]

If that rock was found over in the desert I'd call it lava. If there is any lava in your area, then slag is the next best bet. I don't see any peacock color, but in one picture it's almost peacock, and that would be low grade copper.

 

[homestead hunter]

definitely slag or the term clinker comes to mind

 

[redvictor1]

I agree it does look like lava...

This rock was found in North Carolina in close proximity to a large quartz vein, tons of slate, and a mine shaft from the 1800's. Interesting about Peacok color....When I viewed the metalic areas under the scope, i did see purple, green, gold, silver & even copper colors. This didnt show up in the photos I posted.

 

[BosnMate]

Sounds like maybe it's slag (clinker) with some copper in it.