About Meteorites

Meteorites are space rocks- it’s really that simple. For a slightly more detailed definition, meteorites are chunks of rock or iron that have fallen to earth from space which originated from a celestial body. These can include comets, asteroids, planets, and moons. Meteorites come in all shapes and sizes- some are big, some tiny. Some meteorites that have hit Earth have been so large that they left huge craters. The one thing they all have in common is that they originated from space.

Collecting Meteorites

Collecting meteorites can be a great rewarding and educational hobby. But reader beware, it’s addicting!  Viewing a meteorite gallery at a museum can be an intoxicating experience. There is something to be said however for having your own collection. Physically holding a rock from a celestial body is beyond words, and becomes an obsession for many of us.

Collections normally start off small and grow rapidly depending on individual budgets (yes… it can get pricey, but does not need to be). Many meteorite collectors begin their collections with a common ordinary chondrite or even a small iron such as Campo del Celio. Eventually, the collector obtains a variety of specimens and begins to narrowing the scope of their collection. Some focus on historical meteorites, others on observed falls, and yet others by type, shape, or location.

Naming of Meteorites

The official committee tasked with assigning a name to a particular meteorite is the Nomenclature Committee of the International Society for Meteoritics and Planetary Sciences (The Meteoritcal Society). The Committee has established guidelines for naming meteorites which generally associate a name with the location of where the meteorite or meteorites were found. The complete guidelines can be found on the Meteoritical Society’s Website.

As part of the process of assigning an official meteorite name, the Committee designates each meteorite as a fall or a find. A fall indicates that the meteorite was observed falling to the ground (known as a meteoroid) or even exploding overhead (known as a bolide) and the meteorite in question originated from the observed meteoroid or bolide. A recent notable example of an observed fall is the Chelyabinsk meteorite which exploded over Russia in 2013 or the Park Forest meteorite which was observed over Chicago, USA in 2003. A find indicates that a meteorite was found in a certain location but was not observed to have fallen. If the exact location of a meteorite is unknown, the location of purchase or discovery is normally used and is documented as such.

Once the Committee decides on the name and designates the meteorite as a fall or find, the last step prior to receiving an official name is to add classification data from a Meteoriticist (scientists specializing in meteorites). This data includes a visual and compositional description of the meteorite, its chemical makeup, and suggested class or group the meteorite associates with. If all of the data is valid, the Committee votes on each submission and make the name official.

Classification of Meteorites

Meteorites are grouped by Meteoriticists into several distinct classes: Stony, Iron, and Stony-Iron. Each class is further divided depending on specific characteristics. Here are the basics for the most commonly encountered/discussed meteorites:

  • Stony Meteorites

    • Chondrites (C)

      • Ordinary (OC)
        • High Iron (H)
        • Low Iron (L)
        • Low Iron, Low Metal (LL)
      • Carbonaceous (CC)
        • Vigarano-like (CV)
        • Karoonda-like (CK)
        • Ornans-like (CO)
        • Mighei-like (CM)
        • Ivuna-like (CI)
        • Bencubbin-like (CB)
      • Rumuruti (R)
      • Enstatite (E)
      • Ungrouped (C-UNG)

     

    • Achondrites (ACH)

      • Astroidal
        • Vesta (HED)
          • Howardite (HOW)
          • Eucrite (EUC)
          • Diogenite (DIO)
        • Angrites (ANG)
        • Aubrite (AUB)
        • Ureilite (URE)
        • Brachinites (BRA)
      • Primitive
        • Acapulcoite (ACA)
        • Lodranite (LOD)
        • Winonaite (WIN)
      • Ungrouped (ACH-UNG)
      • Lunar (LUN)
      • Martian (SNC)
        • Shergotites (SHE)
        • Nakhlites (NAK)
        • Chassignites (CHA)
        • Basaltic Breccia (BAS)

 

  • Stony-Iron Meteorites

    • Mesosiderites (MES)

    • Pallasites (PAL)

      • Main Group (PMG)
      • Eagle Station (PES)
      • Ungrouped (PAL-UNG)

 

  • Iron Meteorites

    • Magmatic

      • IC
      • IIAB
      • IIC
      • IID
      • IIF
      • IIG
      • IIIAB
      • IIIE
      • IIIF
      • IVA
      • IVB
    • Non-Magmatic

      • IAB
      • IIE
      • Ungrouped (IR-UNG)