Re: Can someone identify this rock?
- From: "coastwatch" <coastwatch@xxxxxxxxxxxxxxx>
- Date: 9 Jul 2006 13:29:56 -0700
coastwatch wrote:
Ken wrote:
I found an interesting "rock" the other day. I originally thought it might<snip>>>
be a meteorite because of the spherical structures within the rock. As you
will see if you click on the links below, this "rock" seems to be broken off
from a larger piece. There exists many spherical structures.
---What you have appears to be a concretion, looks ferruginous
(containing iron minerals) - common in sedimentary rocks. This will
show a "Gobstopper" like concentric internal structure in many cases.
Cheers,
Nigel Whittington
Hull
U.K.
I had misinterpreted your description of "Spherical Structures" as
being internal to the whole specimen, but I now think you mean the
lighter coloured patches visible on the surface. Liiking at the broken
corner of the piece I thought I could see some evidence of internal
layering, but the picture is not quite clear enough.
I wonder if the "Spherical Structures" are reduction spots
You can get reduction of some ferric oxide (Fe2O3) to ferrous oxide
(FeO), which is slightly soluble. Leaching of the reduced iron caused
the colour to change to green, or colourless.
Not "Orbicular Granite" - you would see visible crystaline structure,
even in the images posted - search for "Baltic Brown" using your
favoutite search engine to see examples of a well known example of
Orbiculite - what you have is NOT that!
( Strike one against Don Findlay)
Cheers
Nigel
Hull
East Yorkshire - the Ice Age Coast
.
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- From: Ken
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