Copper Slag?

[agbkyle]

Hi, I'm new to this forum. I'm from Southeast Mass. Found this next to a river in the woods.
Rang up as copper and is green so I'm assuming it is copper.
Just wondering how to tell if it's an artifact or the result of a melted copper blob.
Search on the internet for "copper slag" shows a couple like it and they're in museums.
Thanks for any info

 

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[CoolFrayers]

It looks as if it was something from a foundry.
I lived in the U.P. of Michigan for years and was always finding Copper pieces from in old abandoned mines (shhh, dangerous and not advised)
Yours has the look of something that a foundry would have produced; very high temperatures create excessive bubbles, then when cooled quickly they stay as very round bubbles. When the pieces are broken, they create very sharp edges around the bubbles.....
Here is raw copper uncleaned:

And cleaned raw copper:

We used to get huge pieces, and they did not look quite like yours...just my opinion however.

 

[Evolx10]

Im no expert but slag is more impurity than metal i believe. Its skimmed off the top of molten metal in foundries and tossed. the inside of some of the broken bubbles on yours have that dark black/brown glassy look that alot of slag has. And if its from copper it might contain enough to get a green patina.

and coolfrayers: if those are shining up looking like a brand new Lincoln like that i don't think they are slag but rather just copper -ore maybe- .

 

[tulecanyon]

native copper and slag are two different items.
slag is the waste by product of smelting metal.

the piece you posted is not waste. perhaps a smelter spill.