[meteorite-list] Wierd Meteorite Wrong Question?

From: greg stanley <stanleygregr_at_meteoritecentral.com>
Date: Mon, 6 Apr 2009 11:19:47 -0700 (PDT)
Message-ID: <708945.40761.qm_at_web52305.mail.re2.yahoo.com>

Adam:

From your picks I would say one of three possibilities, although remember nothing is for sure from the photos on the web. I really need to view specimens with a hand lens.

Poor grade jasper ? I have found this everywhere. They can be magnetic if it contains hematite and iron oxides. Although the contraction cracks are not very common in the jasper I have found. A hardness test will verify this ? Jasper is hardness 7.

I fine grained quartzite with desert varnish ? I have found these to. They look igneous to me. Some are gray, reddish or brown- the grains can very fine. I have found some very dark. They are usually not magnetic. If you look with a hand lens you can see very small grains with a darker coating on them. And as always ? look for any sign of quartz.

I siliceous mudstone ? This stuff I have found and been fooled; have even sent samples to UCLA. The color looks very much like a weathered chondrite. They sometimes are weakly magnetic, but tent to be not as dense as a stony meteorite. When cut, they have swirls inside and look very similar to the Jasper or a reddish basalt, but are softer. I friend of mine calls them ?siliceous ooze.? I believe they are formed in an ancient mud settled in a shallow ocean.

In the Mojave Desert I have found many rocks with all variations of ?Desert Varnish,? some coatings on rocks of from bacteria; they can be very tricky, but I keep every one and take it home as you never know.

In your specimen the contraction cracks and high density are good and the fact there was nothing similar is a good sign.

Looks like you have to cut it to make sure.

Greg Stanley
Bakersfield

--- On Mon, 4/6/09, Adam Hupe <raremeteorites at yahoo.com> wrote:

From: Adam Hupe <raremeteorites at yahoo.com>
Subject: [meteorite-list] Wierd Meteorite Wrong Question?
To: "Adam" <meteorite-list at meteoritecentral.com>
Date: Monday, April 6, 2009, 10:14 AM


Dear List Members,

We went on a Mojave Desert hunt this weekend where I found this weird stone.? My questions is, does anybody have a clue to what type of rock this may be?

The reason I am asking the list is that several hunters have thousands of hours in the Mojave whereas I only have a couple of hundred and they may have seen something like it before. It is very dense, has surface contraction cracks and is not attracted to a powerful magnet at all.? It does look like a crust but not like anything I have ever seen before.? I have never observed a gray crust on a meteorite is what is convincing me that it is terrestrial. I have never seen surface contraction cracks on a terrestrial rock that did not penetrate the whole stone.? We must have hiked 20 miles and I did not come across anything similar.

We thought it was a meteorite when we first saw it in situ but now are not convinced. I do not want to cut it if it is not a meteorite because it would be one of the best wrongs I have ever seen. On the other hand, if there is any chance whatsoever that it could be the first North American Lunar, I would cut it in a heartbeat. Maybe, I am just dreaming but I am convinced that within the next 10 years, some lucky hunter will find one.

Images of the stone:

Image 1
http://themeteoritesite.com/Achondrite-1.jpg

Image 2
http://themeteoritesite.com/Achondrite-2.jpg

Any input would be greatly appreciated.

Best Regards,

Adam



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Received on Mon 06 Apr 2009 02:19:47 PM PDT