What are these shiny black rocks I keep finding randomly around my chicken coop? : r/geology

What are these shiny black rocks?, Page 2

Sedimentary rocks in the field by Visokovisoko - Issuu

What are these shiny black rocks?, Page 2

Mineral-Stained Bluffs (U.S. National Park Service)

Molly, one of my beautiful Black Rock chickens., Beverley

Rock Tumbling 101: Beginner's Guide to Polish Rocks - AB Crafty

What are these shiny black rocks I keep finding randomly around my chicken coop? : r/geology

Chicken Keeping FAQs

What is the ideal humidity level for a chicken coop? - Quora