Possible meteorite?

[JamesH]

Hi, i'm new to the forum and was hoping that someone here could help me identify a rock I found last tuesday, or steer me in the right direction.
I found the rock in Pontllyfni at the very top of the beach, where the land meets the shingle. I know the coast is not regarded as the best place to find meteorites, but curiosity got the better of me, so I stopped to have a look around.

Anyway, heres a link to a few photos:-
https://picasaweb.google.com/1110493505 ... 0OzRm-qLIA

The rock has a mass of 413g and a density of 3.12g/cc3, it feels quite hefty.
It seems to have a dark outer layer, possibly a fusion crust? The matrix is a bit lighter colour which can be seen on the brocken face. There are a few rusty patches on both the broken face and the outer layer.
Most interestingly, the interior of the rock is composed of small spherical chondrule like particles mainly under 1mm, with a few up to about 2mm
The rock is only very weakly attracted to a magnet - its evident when a magnet is suspended on a thread.

Any advice would be very much appreciated, many thanks
James

[Matt Smith]

Hi James,

Thanks for the post. My guess would be that your find is Haematite. Could you try a "streak test" ( http://meteorite-identification.com/streak.html ) and let us know the result?

Interesting search location though, were you specifically looking for meteorites? One did fall at Pontllyfni 80 years ago and it has been suggested that a larger mass from the fall may have landed in the sea. The Pontlyfni (excuse the different spelling, but that is the recognised name of the meteorite. http://www.lpi.usra.edu/meteor/metbull.php?code=18865 ) meteorite is a rare type called a winonaite, but not likely to be a good visual match to your stone either.

Cheers,

Matt.

[Entropydave]

OMG - wouldnt it be amazing if it was a piece of Pontlyfni?!!
I remember seeing the main mass at the NHM....
Alas, I feel pretty confident it is not more of this exquisitely rare meteorite.... FYI I don't think I have ever seen it in a private collection or for sale....

[msg-meteorites]

Now that really would be a find and a half! I think Pontlyfni is unfortunately firmly on the non available list until some is prised away from the NHM

[JamesH]

Sorry for the late reply guys, i've had a real hectic month at work.
Matt - the streak test gives a slight dark brown streak on the exterior, the interior gives only a very slight greyish brown line.
Wouldn't heamatite give a terracotta coloured streak?
I tried to take a photo of a chipped surface through a 10X loupe, I appologise for th poor quality:-
https://picasaweb.google.com/1110493505 ... 0784990034

Last weekend I found a tiny piece of rock at a completely different location, a couple of miles from my home on the llyn peninsula. I found it using my meteorite cane. It's only very small, about 3x5mm and is quite strongly attracted to a magnet.
It appears to have what looks like fusion crust, there are also several cracks in it. The crust appears to be chipped in a couple of places, a few nodular protrusions can be seen here and several through the crust.
Now, the most exiting feature. I ground a small window in it and what I found were metallic flecks, clearly in the shape of a ring! Could this be an armoured chondrule!?
Heres a few photos taken through a 10X loupe, again the quality is poor:-
https://picasaweb.google.com/1110493505 ... 6_C33-PgPQ
What do you think?

Cheers

[Kieron]

Hi James,

I wonder if your first stone might be some form of oolitic ironstone - I have been fooled by this more than once because the ooliths do have a passing resemblance to chondrules.

As for your second piece, here is another test that you might not know. Place the stone on your magnet (held horizontally) and see if it aligns itself in a certain direction - if it does then it is likely to be terrestrial. Looks like an interesting specimen anyway.


Regards, Kieron

[JamesH]

Thanks for the input Kieron, thats a strong possibility. Is there a method to confirm or rule out oolitic ironstone?

As for the second specimen, it will stick to a magnet in pretty much any position. It doesnt seem to have a prefered orientation.
That test is a new one to me, thanks. Whats the reasoning behind it?

[Kieron]

Hi James,

If you have access to a microscope you could look for concentric ringing within the ooliths. See here for an example, and note that the ooliths are more egg-shaped than circular:

http://www.northeast-geolsoc.50megs.com ... on.htm#top

Regarding the magnetic alignment, don't quote me, but I believe the magnetic orientation of terrestrial rocks is fixed at the time that they are formed. This link will explain it better than I can:

http://en.wikipedia.org/wiki/Paleomagnetism


Regards, Kieron

[Kieron]

Hi Folks,

Just to come back to this subject, here is a snapshot of one of my recent finds that I suspect is some kind of oolitic ironstone. Note the rust patches - this stone gave a fairly strong signal with my metal detector. The larger ooliths are about 2mm across.


Regards, Kieron

[rydermadness]

after reading the link http://en.wikipedia.org/wiki/Paleomagnetism i was wondering what you guy's think of this youtube video do you think it is credible? it makes a lot of seance to me. http://www.youtube.com/watch?v=ohwrb9Si ... 4w&index=1