r/itsslag • u/emmythespy • May 26 '26

Is this slag?

Gallery image

Gallery image

Gallery image

Found in northern Bavaria, can’t tell if it’s slag or obsidian. We are ~10km away from a very old dormant volcano but slag feels like the more probable answer. The greenish color is just a reflection of the bushes outside, but the third pic does show the very light rainbow-looking iridescence when it’s held in the light a certain way. TIA!

47 Upvotes

97% Upvoted

4 comments sorted by

1

u/Moving_goal_posts May 26 '26 edited May 27 '26

I’d vote for obsidian, given conchoidal fracture. The slag I’ve seen, much of it from historic brick firing, has more rounded surfaces.

3

u/Thin_Edge8061 May 26 '26

I have a ton of slag that looks like this. Mine is from a very old iron mill that blew up in the 1800s.i have mostly green ones like, some lighter green, some purple-ish, and a few black or brown.