Meteorites fall to Earth more often
than you might think, but most rocks that get brought in to us are not
meteorites.
If you have an unusual rock, it might be a meteorite if:
- It is really dense. However, many
ore minerals are also quite dense, and Missouri is rich in ore minerals.
- It is magnetic. This suggests the
presence of metallic iron, although the iron oxide mineral magnetite
is also magnetic.
- It is solid with no hollow pores.
(Meteorites may be fractured, but no meteorites contain pores.)
- If a corner of the sample is ground slightly,
the interior should be, or at least contain, areas that are metallic
and silvery.
- If a sample passes tests (1) through (4), it is possible that you
have an iron or stony-iron meteorite. There are also some kinds of
meteorites that are almost indistinguishable from igneous rocks formed
on Earth, and these often go unnoticed. The best supporting evidence
that you have a meteorite is that you saw it fall from the sky and
collected it from the large crater it made when it landed.
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Picture
(1) shows a sliced iron meteorite.
This sample is smaller than a softball but weighs over a pound. |
Picture
(2) shows another slice of iron meteorite.
This sample has been polished and etched, to show the "Widmanstatten"
crystalline pattern that is a unique characteristic of meteorites.
The sample is a little over 1 inch across. |
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Picture
(3) shows a lump of hematite
(iron oxide, a common mineral in Missouri).
This is non-magnetic and, when a corner is sawn off,
the interior is non-metallic.
This is not a meteorite. |
Picture
(4) shows a polished slab of petrified wood.
This is an example of a "meteor-wrong." |
For more pictures of meteorites,
and "meteor-wrongs," see the following:
To find out a bit more about how meteorites form, follow these links:
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