I found this on the web. Maybe be your rock. Came with this description.
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On initial look..this does look like a rusty iron in the Campo/CD class however since it broke in half it is obviously not. The Piedmont of The Carolinas and Georgia are common with this kind of material.
Near as I can tell it is a iron cemented (limonite) sand-bearing liner of a a hydro-thermal /vuggy fracture through bedrock within what was either an organic limestone that has completely weathered away leaving the casting--or these are castings from organic material which was buried in loosely consolidated sand. I have found them either way including a few tree branches and fossil cones replaced by this mineral combo. I just found some in Virginia that was so realistic looking that I was sure [ it ] could be a meteorite. The iron content was so high that it rang like an iron and so hard that my hammer left a metallic mark! Apparently sometime in the middle mesozoic there was a sudden rise in oxygen which precipitated iron out of the water. The iron acted like a cement and some of this material is very resistant to breaking. Some on the other hand is very friable and crumbles in one's hand.
I have several samples and some even have relic micro crystals. The limonite can also take the form of red and yellow ocher, which the Indian's powdered and used for pigment.
