I'm curious if there is a way to test if this sample might be Martian andesite.

What type of oxygen isotope (or other) test can be done to address this in some way?

As background, any information about such tests at the University of Utah would also be helpful to know.

enter image description here

  • $\begingroup$ This is Rob biddle.my results on oxygen isotope test was."not a meteorite it happens to be a rock from the ocean floor next to hydro thermal vent".i said give me a week i will explaine why. $\endgroup$
    – Rob B
    Commented Feb 25, 2020 at 8:47
  • $\begingroup$ @RobB Please see here about merging your accounts: space.stackexchange.com/help/merging-accounts $\endgroup$
    – called2voyage
    Commented Feb 25, 2020 at 13:58

2 Answers 2


If this is something that you have found (rather than purchased as a meteorite) the chances are very small that it is a meteorite. Even if it is a meteorite, the chances it's a Martian one are even smaller still and none have been found in the United States.

According to the Meteorites in the US page, which draws from the Meteoritical Society database, only 1821 meteorites have been found in the US over the past 200 years. Of all meteorites found in the world, less than 0.1% are from the Moon or Mars (source statement, graphs of meteorite fractions) and none of these have been found in the US, with the vast majority (99%) found in Antarctica or the African or Arabian deserts (lunar meteorites)).

There is a long "Meteorite Realities" page and a shorter, graphical "Self-Test Check-List" that it would be good to check and go through before it gets to chemical testing.

If you are determined to get testing done, the same meteorites.wustl.edu site on its page on meteorite chemical composition recommends chemical testing by Actlabs; there is more information on what they need (a 5g sample) and the type of tests to ask for on this page. Andesite is a type of basalt formed by volcanism and while it is true that most of the Martian meteorites are basalts (as discussed here), so are a lot of Earth rocks. On the chemical composition page, in plots of chemical composition such as silicon dioxide (SiO$_2$) vs total iron and magnesium oxide content e.g. chemical composition plotsthe martian meteorites (red squares) separate from most terrestrial/Earth rocks and the "meteorwrongs" (white circles) due to having higher iron+magnesium content in the form of pyroxene, olivine and ilmenite (from 'Chemistry' section of How Do We Know That It’s a Rock from the Moon?) However as noted on the basalt page:

Unfortunately, the only way to distinguish a terrestrial (Earth) basalt from a basaltic meteorite (Moon, Mars, asteroid) is with expensive chemical and mineralogical tests. If you find a basalt, it's probably not a meteorite.

So I would guess that these additional tests for the contents may be enough to distinguish a non-Earth basalt from an Earth one when the appearance to the eye or under a microscope is very similar (due to the similar formation mechanism via lava). However additional tests needed for trace elements may also be needed (Lunar basalts are Chromium-rich but have much lower concentrations of the alkali elements of potassium, sodium, rubidium, and cesium)

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    $\begingroup$ xkcd.com/1723 $\endgroup$
    – user8021
    Commented Nov 13, 2019 at 8:27

Only two meteorites have been found on Earth that are composed of andesite. They were found at the Graves Nunataks ice shield in Antarctica during a US Antarctic search for meteorites in 2006/07. The meteorites are labelled GRA 06128 and GRA 06129.

Geologically, the samples are unusual because they are rare samples of felsic crustal material and they are extraterrestrial. Another thing that makes them unusual is,

these rocks also have unusual, isotopically light iron isotope compositions (negative values of δ56Fe). In contrast, all other planetary crust materials, including Earth's felsic crustal rocks (granites and andesites on the plot), have heavy iron isotope enrichments (positive values of δ56Fe).


The low NiO and low Fe/Mn of the mafic minerals in GRA suggest that its source was depleted of Ni and Fe relative to a chon-dritic precursor. Such depletions in eucrites and Martian rocks are interpreted to reflect segregation of metal via core formation; a similar inference could be made for the GRA parent body.

Sourced from a NASA Technical Report.


The meteorites’ composition has led scientists to rule out the possibility that they are chips off of the Moon, Mars or Venus. And the ratio of iron to manganese does not match that of Earth, ruling out the possibility that it is an old chunk blasted off our planet’s surface that later returned.

By measuring the radioactive decay of elements in the meteorite ...

shown that the rock must have formed around 4.5 billion years ago, when Earth and the other planets were coalescing.

Studying these fragments of a now-vanished object from that era provides a rare window into the early solar system


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