Why this rock is probably not a meteorite:

I found this photo on eBay. The seller claimed the item to be a slice of a rare kind of meteorite, a mesosiderite. Actually, the words were "unclassified Rare Mesosiderite Stony iron meteorite." "Unclassified" is a euphemism for "this rock has not been authenticated as a meteorite by the scientific community." The seller provides no information to back up his claim that this rock is a meteorite. The ad mentions that the rock has "beautifull [sic] chondrules," but I can't see any in the photo (and, I think that mesosiderites don't contain chondrules, but I may be wrong).

There's a lot of mumbo-jumbo about magnetic susceptibility, which can be a quick and useful property to test and identify some kinds meteorites (e.g., Rochette et al., 2007). A measurement of magnetic susceptibility may be able to show that a rock contains metal, but it cannot prove that the metal is an iron-nickel alloy (meteorite) as opposed to just iron (slag).

The rock does not look like a meteorite to me. It has lots of vesicles. Mesosiderites don't have vesicles. If the bright spots are iron metal, then they're not shaped and distributed like metal in a mesosiderite.
  
What is it?

If the bright spots are metal, then it's probably a piece of slag

There are many legitimate meteorite dealers who sell real meteorites on eBay. There are also good people who sell rocks that they think might be meteorites, but who really don't know anything about meteorites, so they're probably wrong. Finally, there are a few nasty people who sell funny-looking rocks that they know are are not meteorites. Caveat emptor.
  


Meteorwrong Identification of eBay
Wrongs and Unverified 'Meteorites' on the Web

www.catchafallingstar.com
www.catchafallingstar.com


Prepared by:

Randy L. Korotev


Department of Earth and Planetary Sciences
Washington University in St. Louis


Please don't contact me about the meteorite you think you’ve found until you read this and this.

e-mailkorotev@wustl.edu