And I do mean tiny.... A while back I got some fossil gravel from Aurora, NC & found these while digging through it. Itty bitty, teeny tiny septarians. The smallest (pic 2) is 2.5mm at it's longest point. The 3rd pic is a nakee one. All the original rock is gone, just leaving the mineral filling. The largest (last pic) is just shy of 9mm. And yes, I almost went crosseyed finding them. And no Joe, you can't try to cut & polish them. 

Discovered. The gravel is sold for fossil searches, from the same local as the public pile near the museum. I've seen nothing concerning the septarians being found in it, but then again, I was checking the tiny bits I would find for fossils. I wasn't expecting to find those at all.