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OutdoorsmanSteve

Coral Fossil?

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OutdoorsmanSteve

Hello all,

I have a find from southern New Jersey. It has many crystalized "veins" running through it, and possibly internal too having a specific gravity of 2.27.....It is not brittle and is very solid, yet lightweight. Underneath shows an off-white color spot, which may be the original color as it has iron color to it now? Any thoughts on this specimen would be greatly appreciated. Thank you for taking a look.

P.S. - Some photos were labeled too large, so I will also provided a link to a photobucket page with more pictures.

http://s935.photobucket.com/user/TheeWoodsman/library/red%20rock?sort=3&page=1

post-17215-0-96498500-1419692455_thumb.jpg

post-17215-0-04416800-1419692472_thumb.jpg

post-17215-0-06281300-1419692484_thumb.jpg

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cpsheridan

Hiya Steve, Chris S. here...I also live in S. Jersey. We get a lot of Paleozoic corals both rugose and tabulate corals redeposited into Pleistocene sediments of the Cape May, Bridgeton and Pennsauken Fms. They are silicified and quite tough. Recall their original calcium carbonate framework was in the form of calcite rather than aragonite...hence are actually more likely encountered than the later scleractinian corals. My guess is that you have a Favosite sp. there of Devonian age who's original home was where NE Pa or Southern NY State is now. After mineralization it survived erosion better than the surrounding rock...after geological upheaval (mountain building) rivers and ice ages...we get them down here. That's my guess anyway. CPS

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Harry Pristis

Looks to me like a crystalline mineral. I see no evidence that this was ever any sort of coral.

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Ludwigia

I agree with Harry. Probably mineral or a pseudomorphosis of one into another. I also don't see the typical evidence of coral in the form of corallites, columna or septa.

Edited by Ludwigia

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Auspex

I agree that it is not coral, and may not be of organic origin.

The only fossil trace that it reminds me of is something like Skolithos.

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OutdoorsmanSteve

Thanks everyone for your reply's thus far, I'll for certain look into them. Its always intriguing comparing opinions and hypothesis on the origin of rocks/fossils. I appreciate your inputs.

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OutdoorsmanSteve

Question? Can I learn anything from the crystallization or crystals themselves about this specimens history or making? Thanks

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Ludwigia

Yes you certainly can, but I'm not advanced enough to be able to help you further. What you need is advice from a mineralogist.

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howard_l

Without knowing the age it is hard to tell but there is a Paleozoic "coral" called Tetradium that resembles your specimen. If you had a way to grind and polish the end of the rock, it might show what looks like soda straw like ends. If it does it could be Tetradium. I have included a few pictures off the net of examples of Tetradium. There is some question if Tertradium is truly a coral.

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post-6251-0-05036000-1419904168_thumb.jpg

post-6251-0-96272900-1419904187_thumb.jpg

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OutdoorsmanSteve

Thank you for your posts. I will try and find a mineralogist to talk to and will look deeper into tetrtadium. I appreciate your input as always, thanks again.

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howard_l

You should try to determine the hardness, It looks a like could be chert replaced. See if it scratches glass.

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OutdoorsmanSteve

Thanks for the suggestion. I did two tests...one on a penny and one on glass, in both cases it was able to scratch and appeared to suffer no damage to itself.

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howard_l

What ever it is I suspect it is chert replaced. Minerals can be altered and replaced by silica (which is what chert is) and fossils can be replaced by chert from their original composition of calcite or aragonite (which is a form of calcite). The biggest question is what is its age. If it was found in a stream that drained numerous units of different ages that will be hard to determine. The only thing I can say is to go out to the location where this was found and look for other fossils that are index fossils (fossils unique to a certain age). If some can be found and they have similar replacement, we can infer that they came from the same unit and age. This of coarse is not exact science but the only other way would be to follow the replacement material up stream until the material was found in place, which could be a huge undertaking,

Short of that I would find some way to grind and polish an end of the rock to examine it for more detail. Check to see if you have a local rock club and some one who does lapidary, they might be willing to do it for you for free, it would only take someone a few minutes with the right equipment to do it.

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Ludwigia

I find the idea of chert replaced aragonite is certainly worth following up.

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OutdoorsmanSteve

This sounds like a great lead, thank you so much for offering it. As always I will try and follow it up and will post if I find anything....thanks everyone the ideas are very appreciated.

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