Why this rock is probably not a meteorite:
They are meteorites.
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What is it?
Coincidentally, I obtained this image in an e-mail advertisement from
a dealer the same day as I
received the previous photos. They are good photos (and free), so
I've included them here.
Vaca Muerta is a well known meteorite. Many pieces, some up to 25
kg in mass, have been found in the Atacama desert of Chile. It's a
rare and interesting type of meteorite - a mesosiderite. Mesosiderites
contain silicate minerals, like chondrites, but they contain much
more metal.
If you've been following all this over the past 47 photos, you might
be thinking, "Well, Dr. Smartypants, how come these rocks aren't
smooth and aerodynamic? Is that what a fusion crust looks like?"
I think I have the answers.
These are all fragments of a large meteor. Pieces of Vaca Muerta have
been found 100 miles apart. That means that the meteor began to break
apart as it entered the atmosphere. Some fragments may have broken
off after most of the surface ablation had already occurred, which
would lead to angular fragments with little of no fusion crust. Also,
I suspect that large, metal-rich meteorites don't ablate to rounded
stones like small stony meteorites do. The heat of ablation is conducted
into the meteorite and away from the surface faster for metal
than for silicates.
If these rocks weren't so full of metal and they hadn't landed in
a desert, they would be easy to overlook as meteorites. The top and
maybe the bottom fragments seem to have some fusion crust, however.
The mass units appear to be in kilograms (kg), not grams (g), in English
usage.
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