Naked Science Forum
Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: HumanEnigma on 05/11/2010 06:42:10
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A few years ago a friend gave me this interesting rock. She said it was a meteorite she had found on her ranch in Texas. I believed her and have held onto it ever since. A while back I found out that meteorites are magnetic, so I though that I would see if mine was. To my dismay, the rock my friend gave me was not even the slightest bit magnetic.
Heres what I can tell you about this rock that you can't see, and might help ID it.
weighs about 46.8 g
volume is near 15.3 cm³
density is around 3 g/cm³
non magnetic
Its metallic-black and rust-brown.
Thanks for all your time, please help me ID this specimen.
http://www.flickr.com/photos/humanenigma/sets/72157625319543654/
(I apologize for my shaky hands, photos are a bit blurry)
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Hello HE
Your links seem to be broken. The ellipses (...) are actually there - not just hiding more info. Try cutting and pasting direct from the url bar at the top of your browser - and perhaps check that they are working afterwards
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Not a meteorite (disappointing news!). But welcome to the forum anyway.
The square "scales" that you see on the outside are weathered pyrite cubes, which is something you won't find in meteorites. Polish is either desert varnish or weathering.
BTW, not all meteorites are magnetic.
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The square scales do make me think that there is some crystal lattice structure, but I have my doubts about it being pyrite. This rock is very stout, not brittle like most pyrites. It looks and feels some what like Hematite, but I don't think it is.
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Some sort of iron oxide- probably a mixture of hematite and limonite. Very likely to have mobilized silica (jasperoid) added.
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Exactly where in Texas as it found. There are several know chondrite meteorite fall fields here and this could be a chondrite.
And the silvery look off the "fresher" surfaces intrigues me.
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The ranch was either in Fredericksburg or Elgin, but I'm not sure which. The silvery metallic-grey parts are what really interest me as well. In person it has a look similar to that of graphite or hematite. Though it is nonmagnetic I have yet to test if a current can be conducted through any part of it, perhaps I'll give that a shot later tonight.
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Hematite nodules can be similarly poopy ...
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http://meteorites.wustl.edu/id/concretions.htm http://www.flickr.com/photos/humanenigma
(http://www.flickr.com/photos/humanenigma/5148070560/sizes/l/in/set-72157625319543654/)
Possibly rusted pyrite : blackened pyrite crystals surrounded by brown rust (iron oxide) ? ...
This concretion appears to have started as a mass of pyrite crystals (iron sulfide, cubic) and is in the process of oxidizing to iron oxide.
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http://meteorites.wustl.edu/id/concretions.htm
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I was under the mistaken impression that hematite was quite magnetic. So, I ruled out the possibility that it could be hematite, but looking at the site RD posted really has be thinking that it might be some form of hematite concretion. However, I am still unsure.
By the way, RD, the rock you have mine paired with is an uncanny resemblance, it's almost scary.