In the “stones I’ve never seen before” category, I recently stumbled across Psilomelane, which… I still know very little about, other than that it’s a somewhat obscure black manganese oxide mineral and it looks like what you’d get if you crossed hematite with heavily banded agate. The patterns are fascinating, sort of like a greyscale version of malachite; it’s heavy for its size and has a beautiful metallic sheen. I paired it with rainbow obsidian in this piece.