I Do Not Classify Meteorites
I do not classify meteorites and I do not provide “Certificates of Authenticity.” I am retired and I no longer have a laboratory. If, based on the information that you provide me, I think that your rock might be a meteorite, then I can probably put you in contact with someone who does classify meteorites. I will not do that unless I am >95% certain that the rock is a meteorite, however. It will likely cost you several hundred dollars to have it classified because classification requires a lot or work and time on expensive laboratory instruments. For amateur finders it is more convenient to find a meteorite dealer who will buy it unclassified as the dealer will have contacts who can classify it. Be aware that most meteorite dealers will ignore you because, like me, they are contacted every day by people with meteorwrongs.
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 that Actlabs sends you (the XLS file) and I will tell you whether the rock composition is consistent with that of a meteorite. A chemical analysis is sufficient for me 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. If it is a meteorite, then a meteorite petrologist is required to classify it and obtain an official name. For example, I can say with 99+% certainty that your rock is an ordinary chondrite from the chemical composition but I cannot reliably tell you which type of ordinary chondrite (H, L, or LL) it is. It will be easier for you to catch the attention of an overworked meteorite petrologist or meteorite dealer if you have have the compositional data.
Do not bother Actlabs (or any other lab) with questions about meteorite identification. They are chemists who are experts in rock analysis. It is not their job to interpret results. They have no one on staff who is a meteorite expert. They do not classify meteorites. They do not offer “Certificates of Authenticity.” I am the meteorite composition expert, which I do for free. Actlabs send persons with meteorite questions to me.
Check your own data with “Chemical Composition of Meteorites.”
If you want to use another lab, that’s OK. At a minimum, I need “whole-rock” data for Na, Mg, Al, Si, K, Ca, Ti, Cr, Mn, Fe, and Ni.
December, 2020: I have received results of analyses of 613 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.
Hand-held XRF (x-ray fluorescence) Analyzers
I know a few meteorite collectors who use hand-held XRF “guns” to recognize meteorites. Most of the results that I have been sent from XRF guns, however, have not been useful to me to determine if the rock was a meteorite. There are at least three problems. Most of the instruments are designed or programed to do analysis of metals, not rocks, so, for example, there are no data for Si (silicon). Second, data for Na and Mg are critical and those elements cannot be determined by x-ray fluorescence in air. Third, it seems that many users do not really know what they are doing. For, example, a fellow contacted me once saying “Big time reputable gold dealer tested it with his X ray gun.” The big-time-reputable gold dealer told him that his rock contained “at least 15% Bohrium,” an element does not occur in nature and the only isotope of which has an ~85 millisecond half-life.