Meteorite Testing

If you are particularly certain that your rock is a meteorite and you really want to convince me (or any other scientist), then I urge you to obtain a chemical analysis at a commercial rock-testing laboratory. I recommend Actlabs. Ask for analysis code Meteorite(ICP/ICPMS). I have no financial interest in Actlabs, I just know they do a good job. First, however, send me some photos of the rock so I get a chance to say, “If that rock were mine, I wouldn’t spend the money to have it analyzed.”

Actlabs requests a 5-gram sample (a US nickel weighs 5 grams). However, they can do the analysis on as little as 1 gram if you request “no LOI” (loss on ignition, i.e., % weight loss when the sample is heated to a high temperature). LOI is sometimes useful, but never critical, for determining whether or not a rock is a meteorite.

Send me a copy of the report (XLS file) that Actlabs sends you and I will tell you whether the rock composition is consistent with that of a meteorite. A chemical analysis is sufficient for me to be able to say “yes, it is” or “no, it’s not” 99 times out of 100. If I conclude that the composition of your rock is not consistent with any kind of meteorite, then I will probably not be able to tell you just what kind of rock it really is. Rock-type identification requires other kinds of tests.

Check your own data with “Chemical Composition of Meteorites

Most of the results I have been sent that was acquired by one of those hand-held XRF “guns” has not been useful for degerming if the rock is a meteorite. I need data for Na, Mg, Al, Si, K, Ca, Ti, Cr, Mn, Fe, and Ni.  

If you have found a chunk of metal that you think might be an iron meteorite, you need to have it analyzed (at a minimum) for iron (Fe), nickel (Ni), chromium (Cr), and manganese (Mn).  Unfortunately, I do not know a lab that does this cheaply.  If somebody out there does, let me know.

December 3, 2019: I have received results of analyses of 547 samples from Actlabs and more than 100 samples from other labs. Only 10 of the rocks were meteorites, all ordinary chondrites. Half of these were from northern Africa or the Middle East and a couple, I believe, were stones that someone had bought or inherited.