This is my first attempt at studying geology.
A year ago I found this stunning rock in the Maumee River here in Northwest Ohio. The rock is very smooth in texture, measures approx 2 cm, and was found in a bed of sand/mud/stones on an eastern river bend. It seems to have magnetic properties, but I see no oxidation indicating a presence of iron, which I imagined would be the most common reason being magnetic.
Location where I found it, showing direction of river, found on east side: