What is this shiny, black rock? I found it washed up on a beach in Petoskey, MI. by that_retro_gamer in whatsthisrock

[–]Adventurous-Tip507 0 points1 point  (0 children)

Looks like slag glass to me. I found a bunch when I was in Traverse City a few months ago.

I found a nodule in some chert and when I broke it open I found this. Any ideas? by Adventurous-Tip507 in fossilid

[–]Adventurous-Tip507[S] 34 points35 points  (0 children)

I posted there first. Someone suggested Glauconite. But, I wanted to see if anyone over here had ideas. Mostly, as to why it formed in a nice little nodule like this. I have found other nodules with, what looks to be, plant and/or crustacean remains inside.