I went out to the creek yesterday to look for a mushroom. No shrooms so I started looking for rocks. This one caught my eye. I could see slick bluish color through the cortex. Very heavy when I picked it up. Took it home and ground a flat and polished it. It’s either serpentine or jade. Serpentine is more common and I’ll have to do a specific gravity test to be sure. It’s one or the other though. About any rock that outcrops in Ontario can be found here in central IL in the glacial till.