Thanks Randy for your added ideas; as you say, the rock in the photo
doesn't appear fractured yet in the second image it appears it is
weathered deep inside, unless it formed in two stages. Good point on
the hematite. I find it in a lot of concretions that people are always
calling meteorites. I believe it was one of these nearly 10 years ago
that got me on the list after a miner and his beautiful daughter both
insisted to me they had seen them fall, in the middle of some desert
devoid of life. Her name wasn't Clementina but the mine was both in a
cavern and through a canyon;-)
This rock would be a great candiditate to put up on your website of
wrongs in my opinion, the interior of the first image is very tricky.
I think you are agreeing that it would be difficult to find reduced
metal in an otherwise hematite rich matrix for terrestrial rocks. Does
anyone else have any thoughts on that (which include natural
meteorwrongs or meteorites?)
Kindest wishes
Doug
-----Original Message-----
From: Randy Korotev <[email protected]>
To: meteorite-list <[email protected]>
Sent: Wed, Nov 30, 2011 1:23 pm
Subject: Re: [meteorite-list] Meteorite?
I measure the specific gravity of most of the rocks that people send
me. The book values for the SG of hematite and magnetite are in the
5.1-5.3 range. I get a lot of hematite and magnetite rich rocks, and
SG's range from 3 to 5. The low ones are usually from rocks with
quartz sand cemented by a lot of hematite or, perhaps better,
hematite diluted with quartz sand.
I also get a lot of rocks that are claimed to contain metal but all I
can see are shiny mica flakes and grains of pyrite or arsenopyrite
that look like metal but aren't. As I say on this page, a good test
is to look at the grains after sawing and see if you can see the saw
marks.
http://meteorites.wustl.edu/id/ordinary_chondrites.htm
If you can't, it's probably not FeNi metal. I'd like to see the sawn
face of the stone in those photos up close.
Ordinary chondrites break apart from weathering in nature because the
metal rusts, causing a volume expansion (like rust blisters under
automobile paint) that fractures the rock making it easier for water
to get in, etc.. That's the only environment I'd expect to see a lot
of hematite together with metal. The rock in the photos doesn't seem
fractured.
Randy Korotev
At 10:00 PM 2011-11-29 Tuesday, you wrote:
Hi Mike and thanks for your opinion. I seem to see some tiny
vesicles but can't be sure; also we can't assume it's metal that's
sparkling and my thoughts are at a density of 3.2 g/mL it is
possibly some sort of basalt. Anyway, it's a very interesting
meteorwrong, (assuming it's a wrong from the streak test which may
be at odds with it being basalt ...). Wonder what Randy would think
about it; the rock was found in the midwest not too far from
him. It'd be a good one for his great site. Probably can strike it
down as a meteorite by thinking about the two tone concentric heart
it has with dendrites coming out (second picture). Still puzzled...
Kindest wishes
Doug
-----Original Message-----
From: Galactic Stone & Ironworks <[email protected]>
To: MexicoDoug <[email protected]>
Cc: Jimski47 <[email protected]>; meteorite-list
<[email protected]>
Sent: Tue, Nov 29, 2011 8:34 pm
Subject: Re: [meteorite-list] Meteorite?
Hi Doug and List,
Except for the grain size, it reminds me of some acapulcoites,
visually speaking. And if not for the metal flakes, it reminds me of
a very finely grained angrite.
Best regards,
MikeG
--
Galactic Stone & Ironworks - Meteorites & Amber (Michael Gilmer)
Website - http://www.galactic-stone.com
Facebook - http://tinyurl.com/42h79my
News Feed - http://www.galactic-stone.com/rss/126516
Twitter - http://twitter.com/galacticstone
On 11/29/11, MexicoDoug <[email protected]> wrote:
Looks like this has been commented on a bit and confirmed as a -
meteorwrong - and apparently streaked reddish since it is commented
that a streak test indicated it was probably hematite. (The color
isn't mentioned, only that the streak proved it was hematite was
mentioned.)
just one comment, it would be nice to have these threads in the forum
since having to sign up on another site if the thread is started there
twists up the thread ...
here are the interior pictures:
http://www.meteoritejunction.com/download/file.php?id=1121
http://www.meteoritejunction.com/download/file.php?id=1122
Also, this stone is stranger in my opinion than that.
The OP mentions it has a density of around 3.1 g/cc and says that
hematite has a density of about 2.7 g/cc, and accounts for the higher
density being caused by metal flakes distributed throughout the
matrix.
Hematite is muich heavier than 2.7 g/cc, after all in broad terms,
40%
of its chemical formula is iron so one, ignoring the packing, could
guestimate the minimum density of hematite at 0.4*(8 g/cc) = 3.2 g/cc,
but given that the oxide has some weight, hematite ought to have a
density of between 4-6 g/cc (and they are around 5.2 g/cc for both
magnetite and hematite, depending on how it 'settles' together).
Probably the 2.7 g/cc referred to was for quartz terrestrial rocks,
not
oxides of iron.
In any case, I wonder if anyone else has experience with metal flakes
in hematite. Hematite one of the most highly oxidized forms of iron
right up there, more than goethite, and what can result when magnetite
oxidizes further. I makes me wonder how you could have metal flakes
survive in a hematite matrix (I don't think this can happen but really
would like to know if anyone has seen this, for all I know there is a
common process that can produce this, though I can't imagine what it
would be unless someone mixed up a batch specially to do it).
ref:
http://www.meteoritejunction.com/viewtopic.php?f=10&p=2860#p2860
Kindest wishes
Doug
-----Original Message-----
From: Jimski47 <[email protected]>
To: meteorite-list <[email protected]>
Sent: Mon, Nov 28, 2011 3:54 pm
Subject: [meteorite-list] Meteorite?
Hope everyone had a nice holiday weekend. I did some meteorite hunting
and
found this stone. I'd like to get some feedback on it.
_http://www.meteoritejunction.com/viewtopic.php?f=10&p=2860#p2860_
(http://www.meteoritejunction.com/viewtopic.php?f=10&p=2860#p2860)
Cheers,
Jim K
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