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Identified
as "Richarton, ILL." possibly Richardton
H5 (North Dakota, fall, 1918). In the closeup on the right,
saw marks are visible in the metal vein. Notice that the metal grains
are typically less than 1 millimeter in size.
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Mocs
L6 (Romania, fall, 1882). In the closeup on the right, saw marks are visible
in the metal grains.
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Two views
of a sawn slice of Independence
L6 (Missouri, fall, 1917), with electronic flash lighting (LEFT, with
millimeter ticks on scale) and natural sunlight (RIGHT). Click on image
for enlargement. Thanks to Karl Aston for the sample.
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Two views
of a sawn slice of Cape
Girardeau H6 (Missouri, fall, 1846), with electronic flash lighting
from two different angles. Click on image for enlargement. Thanks to Karl
Aston for the sample.
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Unnamed Northwest
Africa (NWA) H5 chondrite
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An unnamed,
probably LL, chondrite from the US. Sawn face on left, exterior with fusion
crust on right.
A large slice of a new stone of the L4 chondrite Seminole. There are thousands
of sub-millimeter metal grains in this slice. (See "meteorwrong"
number 273)
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Sawn face of
Harper Dry Lake 036 (L6; find, 2010, CA). This meteorite shows dark veins
of impact melt, a feature sometimes seen in ordinary chondrites. All of
the small (<1 mm) light-colored specks in the image are metal grains.
Millimeter ticks for scale (bottom). Click on image for enlargement (big).
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Chondrules and metal grains on a sawn face of an unnamed chondrite (probably
H5) from northern Chile. (See "meteorwrong" number
273). This photo was taken with natural light from a north-facing
window on a sunny, clear day, so it looks a bit blue. Millimeter scale
in background.
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Here's a sawn face of another unnamed (L?) chondrite showing metal grains
and chondrules. (See "meteorwrong" number
293). This photo was taken with light from a high-intesity desk lamp.
I rebalanced the color to make the gray background be gray. Millimeter
scale in background.
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Ordinary chondrite
pebbles found in the Sahara desert. Most are broken, but a partial fusion
crust is intact on many of them. Notice that despite that all of them
contain metal, they are not rusty colored.
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Three views of the same stone, another
unnamed ordinary chondrite (probably H chondrite) from northwest Africa.
Above left: The unspectacular weathered exterior in direct sunlight.
Above right: A polished, sawn face in direct sunlight. All the
dark areas are alteration rims (rust) around the metal grains.
Right: The same face illuminated by a north-facing window. The
metal grains are more obvious in this view. The rock looks grayer
than it actually is in this view because of the polish and blue lighting.
It is likely that this meteorite fell thousands of years ago. |
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This meteorite violates a
number of the recognition principles that I stress in "A
Photo Gallery of Meteorwrongs." There is no obvious fusion
crust. The surface is not glassy or shiny; there are no regmaglypts.
The exterior has some ridges and one point. It's clearly a broken fragment
of a larger meteorite. If you look closely at the image on the upper left
(click on image to enlarge), however, there are shiny metal grains along
all the protuberances (points, ridges) because these areas have been abraded
from handling. Also, the specific gravity is 3.42,
well within the range of ordinary chondrites.
On the right is one of many fragments
of an L5 ordinary chondrite from Algeria known as Northwest
Africa 869 (L4–6). On the top, the fusion
crust is still intact. Notice that it is smooth with no holes.
The rougher portion on the bottom of the photo is where the fusion
crust as broken off after it fell. This meteorite probably also
fell thousands of years ago and has been exposed to harsh conditions
in the desert.
Note that there is no obvious metal. L chondrites do not contain as
much metal as H chondrites. The rock is moderately magnetic, however.
Click on image for enlargement (big). |
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Above left and right:
Two views (direct sunlight) of an unclassified ordinary chondrite
fragment from the Sahara desert. The fusion crust is dark and smooth.
If this were a fresh fall, it would be shinier. In most meteorites
the fusion crust is darker than the interior.
On the right is the weathered, broken face of the meteorite (electronic
flash lighting). Rusting of the metal grains has led to reddish staining.
Up close, shiny, unrusted metal grains stick out. Click on image for
enlargement (big). |
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