Part of my responsibilities at the meteorite lab is to handle the e-mails we receive concerning meteorite inquiries. These come in on a nearly daily basis and I can easily receive dozens of requests in a week. I don’t mind answering the e-mails as I consider it an integral part of the outreach that we do as a lab. And if I can teach people about what to look for in a meteorite (or meteorwrong in most cases), then all the better. Generally speaking people are pretty good at following our guidelines for e-mailing us: namely, send us a small amount of high resolution photos. We prefer quality over quantity. As I ranted earlier on Twitter, I occasionally receive e-mails with 25+ photos and it’s a temptation to just delete them and move on.
The sad truth is that the vast majority of people that contact me don’t have meteorites. I would love nothing more than to say “yes you have a meteorite!” to everyone that contacts me. Unfortunately, reality says that earth rocks are far more common than space rocks, but with the added challenge that they all look nearly the same. Take for example this one:
Either it has a fusion crust or it’s a weathering patina. And those indentions are either reglamglypts or weathering features. This is one of the few e-mails I’ve received where I had to stop and examine the picture more closely. Generally speaking I get these sort of pictures:
This rock has a shape that is indicative of being in a fluvial setting. Meteorites are not round and, as a general rule, do not contain vesicles. More importantly, meteorites don’t survive long in a fluvial setting and erode away faster than your typical river sediment.
Some of the worst offenders are slag. This is the byproduct of metal production and is routinely confused for being an iron meteorite. Sometimes slag isn’t even magnetic which just completely rules it out as a meteorite.
My favorite meteorwrongs are scoria. I don’t even need to look at the picture for long to know that it’s not a meteorite.
Could I be wrong in my visual assessments? Of course. Identifying meteorites via photo alone is like trying to distinguish between chocolate chip cookies and raisin cookies at a distance. It all looks the same until you’ve bitten into it and was sorely disappointed by the presence of raisins instead of chocolate. Yes, I have trust issues from such experiences, but that’s besides the point. I may not know with certainty what type of rock you have, but I know just enough to determine if it’s from space or not. And if I happen to be wrong, then all the better!
*for part 1, click here*