Why this rock is probably not a meteorite:
Maybe it is. It (top photo) resembles a pallasite, if the grayish
matrix is metal, which one can't tell for certain from the photo.
Olivine grains in a pallasite are usually more euhedral* than this.
Also, if this were a pallasite, it could only have been cut with a
saw. It's not evident that there are any saw marks and the face is
not obviously flat.
*euhedral: crystals completely bounded by plane faces
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What is it?
If it's not a pallasite, we don't know what it is.
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Note added later
The top photo was sent to us by the finder. The bottom photo I took
myself after the owner sent the rock to me. This is a wonderful example
of why I CAN'T IDENTIFY A METEORITE FROM A PHOTOGRAPH. In the bottom
photo, the clasts are clearly not olivine and the matrix is clearly
not metal - the rock is not a pallasite.
The matrix of the rock fizzes (gives off gas bubbles) when a drop
of hydrochloric acid is placed on it. This means that it is composed
of carbonate. It also means that it is not any kind of meteorite.
It's some kind of terrestrial conglomerate. There are carbonaceous
meteorites, but no carbonate meteorites.
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