Weird Magnet Rock Found on Beach

[DeoxyriboNucleicAcid]

Hello,
I have recently found a number of weird rocks on a Long Island beach.
The rocks appear to be iron based.
They have red-brown currosion on them.
They have a red-brown streak, and are very hard.
Metallic Luster.
No APPARENT cleavage, but then again, they look like they are in layers?

I also found that they are highly attracted to a magnet. Even more interesting, I was able to find their polarity (+/-) using some magnets.


Can someone please identify/ tell me more about this mineral/ rock???

[fuhrerkeebs]

Probably just a bit of iron ore or something.

[fuhrerkeebs]

Here's some info on it: http://en.wikipedia.org/wiki/Iron_ore

[DeoxyriboNucleicAcid]

hmm, I found alot of it scattered throughout dunes?

I dont really know how it could have gotten there, besides waves, etc.

[DeoxyriboNucleicAcid]

nice link:) however, there are not only a few iron ores/ oxides, etc, there is ilmenite, maghemite, the list goes on. I'm kindof looking or specifics, but thanks.

[fuhrerkeebs]

There are many underwater iron ore deposits...maybe you live near one

[DeoxyriboNucleicAcid]

hmm? Would you have any recources on those?

[fuhrerkeebs]

Apparently Long Island used to be mined for iron: http://pbisotopes.ess.sunysb.edu/lig/Conferences/abstracts-01/harbottle-abst.htm

[DeoxyriboNucleicAcid]

oh yes, I posted that link before I forgot all about it.

[fuhrerkeebs]

This talks a bit about underwater iron deposits: http://www.digitaltermpapers.com/view.php/d/598.HTM

[DeoxyriboNucleicAcid]

That is pretty close to where I found these, however, it did't sya much about what these rocks/ black sands could be.

[DeoxyriboNucleicAcid]

oh, oops, didnt see the 2nd one, let me check that out...

[fuhrerkeebs]

The first article says "The heavy minerals were found to include magnetite, monazite, thorite, xenotime and garnet."...I'm don't know much about what magnetite looks like or it's properties...but it appears to be magnetic

[fuhrerkeebs]

Well...here's a picture of magnetite...it looks just like the stuff you found: http://homepage.smc.edu/robinson_richard/rocktest/minerals3/images/magnetite.jpg

[DeoxyriboNucleicAcid]

Well, there is one big problem with it being magnetite, and this is thatmagnetite has a dark black streak, while this has a red brown one.

[fuhrerkeebs]

Well it could also be iron ore...

[DeoxyriboNucleicAcid]

you are right thoygh, it does look alot like mine.

[DeoxyriboNucleicAcid]

but which type of iron ore?

[fuhrerkeebs]

You got me there...

[DeoxyriboNucleicAcid]

hmmm, well I sent out an e-mail to someone at webmineral.com (pesky me), so hopefully I will get something from them.

[fuhrerkeebs]

Let me know what it is if you get a reply...

[DeoxyriboNucleicAcid]

Sure (if I get one)

[coquina]

It is very probably limonite.

 

http://mineral.galleries.com/minerals/oxides/limonite/limonite.htm

 

I find loads of it on the beaches of southeast Virginia.

 

It is commonly called "bog iron"

 

http://www.britannica.com/ebc/article?eu=382897&query=groundwater&ct=

[SurfSciGuy]

They just look like bits of weathered iron to me, probably off a ship or something.

[coquina]

When I first started finding it.

 

One of the pieces I found looked vaguely charred - I thought for sure I'd found a meteorite - I took it to the Virginia Dept. of Mines and Minerals and they identified it as limonite.

 

What's really interesting is that you sometimes find extremely detailed casts of shells in it.