Indian paint pot

An informal name for a hollow ironstone concretion, usually a few cm in diameter, composed of hematite and/or limonite and other mineral matter. They are thought to have formed as pyrite concretions in sediments, later oxidised to iron oxides, with the pyrite and sulphur mostly leached away and the oxides forming a hard shell. They can have various powders, clays or ochreous material inside, sometimes wet like paint. https://seaglassassociation.org/2018/09/20/unusual-finds-along-chesapeake-bay/ https://www.garviespointmuseum.com/concretions.php#:~:text=The%20concretions%20found%20on%20the,No%2C%20they%20are%20formed%20naturally.