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Rich VanValkenburg
05-03-2006, 08:37 AM
Since moving out here to the country, I've been finding some pretty strange rocks. I'm one of those types that likes finding wierd rocks but has no idea what I'm looking at. What I've been seeing out here is what looks like a burned lump in various colors of reddish brown, some are cracked and when I've pulled the halves apart, there's a lump of hard clay inside. Almost like cracking an egg open and seeing a whole yoke made of hard clay. Anybody have a clue what I've got here? I can email a photo.

Rich

Fitz
05-03-2006, 08:45 AM
Geologist here:

Sounds like clinker - remnants of burned material from a furnace. Any foundries, rail beds or other sources of combustion in the area now or historically?

Not sure of what to make of the clay centers :eek: . Send a photo along.

Del Lansing
05-03-2006, 08:49 AM
Fossilized bear plop.
Kidding aside, I've found those also. I once had a diamond saw and would cut open stones hoping to find geodes, but would find the clay inside instead. I figured that sometimes on the way to geodes mud would migrate in instead of minerals. Don't know you'd call them, 'clayodes'?

ishmael
05-03-2006, 08:50 AM
Hm. I've got a good solid year under my belt, and I can't quite place a twisted rock with clay in the center. Gonna go with Fitz, something man made. Strange.

Or it could be the tip of an alien invasion. LOL.

Fitz
05-03-2006, 09:22 AM
Del Lansing:

Clay clinker can form naturally too. Coal seams catching fire can bake surrounding clay and soils.

Greno
05-03-2006, 09:22 AM
They are concretion nodules as one of my old professors explained to me. The outside was iron rich sandstone and the insides a clay. I have one around my house somewhere. Mine came from Monroe County, Alabama

huisjen
05-03-2006, 09:37 AM
Around the old smelter in northwest Tacoma, there's an area where they dumped molten slag into Commencement Bay for years. It's referred to as the "Ruston Formation" (sombody correct me here if I'm remembering the name wrong), as though it were a natural geologic formation.

Dan

Rich VanValkenburg
05-03-2006, 11:32 AM
My daughter has my camera, so it'll be a couple days before I can post a photo. I can't find the best sample I've picked up. My wife, um, wouldn't let me keep it. Something about a 53 year old man walking around with rocks in his pockets. Some women just don't understand how cool rocks are.
This area is pool table flat and 28 miles west of Port Huron, Mi. What I saw when they dug the pond was several layers of clay and gravel, so I'd assume this was the bottom of a lake. It's been farmland for years and years with no industry of any kind. All of the samples came from the rubble near the bottom of the pond which is 20 feet deep.

Rich

P.I. Stazzer-Newt
05-03-2006, 11:41 AM
There are a variety of different clay nodule forms - some with really strange calcite inclusions.
Try google for septarian nodules here are some pictures... http://www.geocities.com/rainforest/canopy/1080/septarian_nodules.htm