Meteorite Identification – How To Identify A Meteorite

To understand how to identify a meteorite you must first know the types of meteorites there are. There is a set of identifying characteristics that most meteorites exhibit that will aid in identification.

Typically most meteorites contain iron and tend to be magnetic. They are usually heavier and much more dense than ordinary terrestrial stones due in part to their high iron content. Meteorites contain a higher concentrations of nickel than ordinary Earth rocks as well, and you can use an off-the-shelf nickel allergy test to test for the presence of nickel.

Freshly fallen meteorites will also exhibit what’s called fusion crust. This is a thin veneer of black material that is formed on the surface of the stone as the meteoroid enters our atmosphere. Usually this dark black fusion crust looks very much like charcoal on the outside, and if a meteorite is a stone type then they typically have a lighter colored stone interior that looks much like concrete.

When viewed under magnification the interior of a stone meteorite will show not only the iron flecks inside the stone, but there are small spherical mineral inclusions called chondrules that will be scattered throughout the matrix. The matrix is the material surrounding the chondrules and iron.

Another very important indicator that a stone might be a meteorite are regmaglypts, or thumbprints. These are indentations, ridges, scoops, and depressions on the surface of the meteorite formed through a process called ablation while the meteoroid passes through our atmosphere.

The extremely high temperatures that the meteoroid endures burns away less dense material from the surface of the stone and this creates the rounded curves and depressions known as thumbprints. Thumbprints are called such because the human thumb usually fits nicely in these depressions.

There are 3 main types of meteorites. Stone meteorites, iron meteorites, and stony iron meteorites. As the names suggest the stony iron meteorites usually consist of a 50/50 mixture of iron and silicate minerals. There are two types of stony iron meteorites; pallasites, and mesosiderites and they are a very rare type of meteorite and make up about 1%-5% of all meteorites.

Iron meteorites make up about 5% of all known falls, and though this number will vary from source to source most will agree that this is probably accurate.

Stone meteorites (Ordinary Chondrites) make up the majority, about 80% to 95% of all meteorites that fall to earth. They are called chondrites due to the small spherical inclusions called chondrules. These minerals are formed in the vacuum and zero gravity environment in space, hence the reason for their shape.

To identify a stone type meteorite scientists will perform tests to verify all of the characteristics mentioned above and then classify a meteorite in a lab and send results to the Meteoritical Societie’s Nomenclature Committee for review and naming.

Once classified by a lab, a meteorite is now eligible for a name to be determined usually relating to the place of the find. A perfect example would be the Sikhote Alin meteorite which is an iron meteorite found in the Sikhote Alin mountains in Siberia, Russia.

There is much more to identifying meteorites than simply using the techinques mentioned here, but if you have a stone that meets all these characteristics then you just might have a meteorite.

The best thing to do would be to contact a university like ASU (Arizona State University) or another meteorite expert which can identify meteorites.

There are many places online that will help you determine if your stone is a meteorite. Below is a short list of some good sites to consult.

Meteorite Identification Video:

Meteorite Identification Sites:
Meteorite-Identification.com – http://meteorite-identification.com/ (One of the best sources online)
Aerolite.org – http://www.aerolite.org/found-a-meteorite.htm Geoff Notkin’s site (of the Science Channel’s Meteorite Men)
Meteorite Market – http://www.meteoritemarket.com/metid1.htm
Meteorites Australia – http://www.meteorites.com.au/found.html (Very Good Detailed Photos)
Geology.com’s Meteorite ID Page – http://geology.com/meteorites/meteorite-identification.shtml (Written by Geoff Notkin)
MeteoriteBlog.com – http://meteoriteblog.com/meteorites/ (Written by Eric Wichman)

Hope this helps…

Meteorites USA