ID please

This rock was found in the Piedmont upland, Alabama, in a stream bed.Its ugly too, The color looks better in person ,it has a green light green color.The rock is wet in the picture its black when dry it weighs eight pounds.Ive found these before that have a aqua, black, red,gray,white and green color but not this size. Some of the smaller green and black rocks have bubbles with tiny mica or gold flakes inside. All I know this could be a volcanic glass rock but what kind?

If theres any questions about more detail please ask .Im more of a gold prospector than rockhounder but lately it seems like after rock hounding more often it gets to be more fun .

From the picture it looks like a manmade slag from a smelter. A conchoidal fracture like glass and a hardness about 5,5 ( about the same as steel) would supprt such a conclusion.

It looks like slag to me, also.

Hello again, thats strange if it is man made wonder how all of it got back there in those hills The area it was found in was next to a large hillside by a stream there are railroad tracks on the other side of the stream about 200 feet away .I did notice on the other side of the stream bank, its really a red clay cliff about five feet high, there was another piece buried in the clay a few inches was sticking out it was blue green colored was gonna try to get it but the waters deep on that side the current was slow and really snakey looking a bunch of logs and brush laying around by it.
Heres a picture of black piece that was found ten years ago around the same area this one doesnt have any bubbles.

Heres another picture of dark green rock so dark it looks pure black.This was found five miles away by the edge of a cliff that had sandstone there was some large chunks of sandstone laying around that had this rock in the matrix, tried to get the best piece, it was huge weighed about 125 pounds wasnt able to carry it .

My guess would be that, since there are railroad tracks nearby, a dump of some sorts was also nearby. The stream, which would have changed course over time, is now cutting away at the previous dumping area.

This is happening in Napa now, and the things that are washing out of the bank are old 1890's - early 1900's bottles.

Just my two cents!

Corie