Meteorite question

If you can help, please reply to my email.-

Our museum was recently approached by a gentleman that brought in a
football-sized heavily oxidized "rock". He felt it could be a
meteorite so we have done our best to prove or disprove his theory by
taking it to several rock shops and museums.

For its size, the object is quite heavy for its size and its weight
surprises everyone that picks it up. The rock in question has a
hardness greater than 5.5 and a specific gravity of approximately 7
(these are estimates given by geologists at the local Natural History
Museum). It has oxidized to a dark brown with a hint of red. It had
a small scuff mark on one corner so we hit it with a buffer wheel and
the structure appears to be solid nickel. The rock is non-magnetic
and emits extremely low radiation - less than background in our
office. We believe it is a meteorite - the only other guess is that
it may be slag, but it gave off no sparks at all when we hit it with
the grinder. Any suggestions on how to proceed?

v/r Gordon

"Krztalizer" wrote in message
oups.com...
If you can help, please reply to my email.-

Our museum was recently approached by a gentleman that brought in a
football-sized heavily oxidized "rock". He felt it could be a
meteorite so we have done our best to prove or disprove his theory by
taking it to several rock shops and museums.

For its size, the object is quite heavy for its size and its weight
surprises everyone that picks it up. The rock in question has a
hardness greater than 5.5 and a specific gravity of approximately 7
(these are estimates given by geologists at the local Natural History
Museum). It has oxidized to a dark brown with a hint of red. It had
a small scuff mark on one corner so we hit it with a buffer wheel and
the structure appears to be solid nickel. The rock is non-magnetic
and emits extremely low radiation - less than background in our
office. We believe it is a meteorite - the only other guess is that
it may be slag, but it gave off no sparks at all when we hit it with
the grinder. Any suggestions on how to proceed?

v/r Gordon


Does *sound* like a nickel-iron meteorite. The only sure quick test
celebrates its 200th anniversary next year. The Widmanstätten test involves
cutting and polishing a flat surface in part of the object, e.g., cut off a
corner. Then dip it in a dilute acid solution (not sure what acid or
concentration is best for this, perhaps diluted lemon juice is enough). A
genuine iron-nickel meteorite will show a crystalline structure (the Wid.
pattern), formed by slow cooling of the initially molten metal over millions
of years (in the interior of an asteroid, later broken up through
collisions). Slag definitely won't show this and is usually a lot less
dense than what you say.

You can get hematite nodules that occur through geological processes. These
are also heavy but won't show the crystal pattern, and are usually fairly
regular in shape. Do a search for articles and pictures. You mentioned
football size, but if it is football shape it may be one of these. These
are sometimes mistaken for meteorites but are far more common. A meteorite
usually has characteristic indentations caused by atmospheric ablation
during entry. Hematite nodules are found on both Earth and Mars.

Get back to us with the result, OK?

--
Mike Dworetsky

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