I figured it was chrysocolla or malachite. I recently tumble a pound of malachite. Those minerals clean up well, but they are soft to tumble and you have to be careful.
Lol.
Well first of all I didn't know what it was and was asking because I wanted to sell it.
& second of all there's a best offer option because I don't know how much it's worth.
But thanks for the rudeness & negativity!
I think you ought to post it on the Rocks and Gems forum here on T-Net. To my amateur eye, it looks like slag glass. I think you need another opinion on two before jumping.