Found an odd rock today - help identifying

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Offline RichL

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Found an odd rock today - help identifying
« on: 07/09/2011 21:12:56 »
It's bulbous on the bottom, perhaps it was melted at some point...and it's rather heavy, but does not seem as heavy as I would expect lead to be in this size.  Any ideas?  (If relevent I'm in Calvert County, MD)

« Last Edit: 07/09/2011 23:04:11 by RichL »

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Offline RD

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« Last Edit: 07/09/2011 23:20:59 by RD »

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Offline imatfaal

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Found an odd rock today - help identifying
« Reply #2 on: 08/09/2011 10:09:27 »
Looks like a lump of iron
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Offline damocles

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Found an odd rock today - help identifying
« Reply #3 on: 08/09/2011 15:16:13 »
I would also think iron. Could be meteoric or archaeologic in origin; metallic iron is extremely rare in nature. Was there ever a forge or a welding shop near where you found it?
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Offline RD

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« Last Edit: 08/09/2011 16:10:00 by RD »

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Offline RichL

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Found an odd rock today - help identifying
« Reply #5 on: 08/09/2011 16:31:16 »
It's a very old property.  The current house dates to 1825, but we're told the grounds have been occupied since the mid-1600's.  I don't know if there was a forge or foundry on the ground.  I suspect that's quite possible.  Also the rock was found near our gravel drive.  I wonder if it could have been shipped in with the gravel?

Also a magnet is strongly attracted to the smooth face and a little less so to the rough face.  I don't have a white tile to scratch, but light brown tile leaves some dusty grey residue on the backside of the tile.
« Last Edit: 08/09/2011 17:00:10 by RichL »

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Offline JimBob

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Found an odd rock today - help identifying
« Reply #6 on: 09/09/2011 22:01:39 »
Hematite
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Offline Geezer

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Found an odd rock today - help identifying
« Reply #7 on: 10/09/2011 01:55:46 »
Hematite

We already knew you never open your wallet JB, but what kind of rock is it?
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Offline damocles

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Found an odd rock today - help identifying
« Reply #8 on: 10/09/2011 02:02:11 »
Haematite is so weakly magnetic that unless you had a very strong magnet you would be unlikely to notice it. I think it much more likely that it is a lump of metallic iron, perhaps with some surface oxidation. A foundry or forge origin seems much more likely to me, given the type of place that it was found, and that it is a single lump rather than a "typical" lump.

By the way, a simple displacement density test would very quickly pick up the difference between metallic iron and haematite.
« Last Edit: 10/09/2011 02:03:42 by damocles »
1 4 6 4 1
4 4 9 4 4     
a perfect perfect square square
6 9 6 9 6
4 4 9 4 4
1 4 6 4 1

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Offline JimBob

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Found an odd rock today - help identifying
« Reply #9 on: 15/09/2011 03:30:34 »
I'm sill going with the botrioidial habit of the rock. --- Hematite
The mind is like a parachute. It works best when open.  -- A. Einstein

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Offline damocles

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Found an odd rock today - help identifying
« Reply #10 on: 16/09/2011 00:29:07 »
This is a science forum. A simple experiment settles the issue between my guess and Jimbob's.

Iron density = 7.874.  Weight immersed in water is 13% less than weight in air.
Haematite density = 5.255. Weight immersed in water is 19% less than weight in air.

This difference should be easily detected, and would settle the issue quite unequivocally.
1 4 6 4 1
4 4 9 4 4     
a perfect perfect square square
6 9 6 9 6
4 4 9 4 4
1 4 6 4 1

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Offline Bass

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Found an odd rock today - help identifying
« Reply #11 on: 16/09/2011 03:36:13 »
My vote goes with JB.  Another possibility, with the weak magnetism, is pyrrhotite.
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