Glossary of meteoritics

This is a glossary of terms used in meteoritics, the science of meteorites.

This is a dynamic list and may never be able to satisfy particular standards for completeness. You can help by expanding it with reliably sourced entries.

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• 2 Pallas – an asteroid from the asteroid belt and one of the likely parent bodies of the CR meteorites.
• 4 Vesta – second-largest asteroid in the asteroid belt and likely source of the HED meteorites.
• 221 Eos – an asteroid from the asteroid belt and one of the likely parent bodies of the CO meteorites.
• 289 Nenetta – an asteroid from the asteroid belt and one of the likely parent bodies of the angrites.
• 3103 Eger – an asteroid from the asteroid belt and one of the likely parent bodies of the aubrites.
• 3819 Robinson – an asteroid from the asteroid belt and one of the likely parent bodies of the angrites.
• IA meteorite – an iron meteorite group now part of the IAB group/complex.
• IAB meteorite – an iron meteorite and primitive achondrite of the IAB group/complex.
• IB meteorite – an iron meteorite group now part of the IAB group/complex.
• IC meteorite – an iron meteorite that is part of the IC group.

A

• Ablation – the process of a meteorite losing mass during the passage through the atmosphere.
• Acapulcoite – a group of primitive achondrites.
• Accretion – the process in which matter of the protoplanetary disk coalesces to form planetesimals.
• Achondrite – a differentiated meteorite (meaning without chondrules).
• Aerolite – an old term for stony meteorites.
• ALH – an abbreviation used for meteorites from Allan Hills.
• Allan Hills – a mountain chain in Antarctica where meteorites are concentrated by ice movements and can be easily spotted in the snow.
• Allan Hills 84001 – is an exotic meteorite from Mars that does not fit into any of the SNC groups and was thought to contain evidence for life on Mars.
• Allende meteorite – is the largest carbonaceous chondrite ever found on Earth.
• Amphoterite – an obsolete classification of chondritic meteorites that are now classified as LL.
• Angrite – a basaltic meteorite.
• Anomalous – meteorites that have properties that are unusual for their group or grouplet.
• ANSMET – the ANtarctic Search for METeorites is scientific program that looks for meteorites in the Transantarctic Mountains.
• Asteroidal achondrite – an achondrite that differentiated on an asteroid or planetesimal (see planetary achondrite)
• Asteroid spectral types – classification of asteroids according to their spectra.
• Ataxite – an iron meteorite that has no visible structures when etched.

B

• Basaltic achondrite – a grouping of basalt meteorites (HED meteorites + Angrite)
• Brachinite – either a primitive achondrite or an asteroidal achondrite

C

• C – can refer to carbonaceous chondrite or to an iron meteorite designation (Roman numeral and letter).
• Carbonaceous chondrite
• CAI – an abbreviation of Calcium-aluminium-rich inclusion
• Calcium-aluminium-rich inclusion
• Chassignite
• Chondrite – stony meteorites unmodified by melting or differentiation of the parent body
• Chondrule – millimetre-scale round grains found in chondrites
• Clan – meteorites that are not similar enough to form a group, but are also not too different from each other to be put in separate classes.
• Class – two or more groups that have a similar chemistry and oxygen isotope ratios.
• Compositional type – a classification based on overall composition, for example stony, iron, stony-iron (as introduced by Maskelyne). Can also refer to the composition deduced from spectroscopy of asteroids.
• Condensation – the process of chemicals changing from the gaseous to the solid phase during the cooling of the protoplanetary disk.
• Condensation sequence – the sequence of minerals that changes from the gaseous to the solid state while the protoplanetary disk cools.
• Cosmic dust – small interplanetary and interstellar particles that are similar to meteorites (See Micrometeorite).
• Cosmochemistry – the science of the chemistry of the Solar System, which is based in part on the chemistry of meteorites.

D

• Dar al Gani – a meteorite field in the Libyan Sahara.
• Desert glass – natural glass found in deserts formed from the silica in sand as a result of lightning strikes or meteor impacts.
• Differentiated – a meteorite that has undergone igneous differentiation. (See: achondrite)
• Differentiation – usually the process of a planetesimal forming an iron core and silicate mantle.
• Duo – a grouping of two meteorites that share similar characteristics (see Grouplet).

E

• E – can refer to enstatite chondrite or to an iron meteorite designation (Roman numeral and letter).
• Eagle Station grouplet – a set of pallasite meteorite specimen that don't fit into any of the defined pallasite groups.
• Electrophonic bolide – a meteoroid which produces a measurable discharge of electromagnetic energy (EMP) during its passage through the atmosphere.
• Enstatite achondrite – a meteorite that is mostly composed of enstatite. Usually part of the aubrite group.
• Enstatite chondrite – a rare form of meteorite thought to comprise only 2% of chondrites.

F

• Fall – a meteorite that was seen while it fell to Earth and found.
• Find – a meteorite that was found without seeing it fall.
• Fossil meteorite - a meteorite that was buried under layers of sediment before the start of the Quaternary period. Some or all of the original cosmic material has been replaced by diagenetic minerals. (It is, however, not a fossil).
• Fragment – a part of a meteorite that broke during passage through the atmosphere.
• Fragmentation – the process in which a meteorite breaks while falling through the atmosphere.
• Fusion crust – a coating on meteorites that forms during their passage through the atmosphere.

G

• Group – a collection of more than 5 meteorites sharing similar characteristics.
• Grouplet – a collection of less than 5 meteorites sharing similar characteristics.

H

• HED – abbreviation for three basaltic achondrite groups howardite, eucrite and diogenite.
• HED meteorite – a clan of basaltic achondrites.
• Hexahedrite – a structural class of iron meteorites having a relatively low nickel content
• Hunter – a person who searches for meteorites.

I

• Impact breccia – rock composed of fragments of terrestrial, extraterrestrial or mixed origin fused by the energy of impact
• Impactite – informal term for a terrestrial rock resulting from the shocking impact of a meteor.
• Iron–nickel alloy – an alternative expression for meteoric iron.
• Iron meteorite – a meteorite that is mainly composed of meteoric iron.

K

• Kakangari chondrite – a group of chondrite meteorites.
• Kamacite – a native metal (mineral) found in meteorites.

L

• Lodranite – member of a small group of primitive achondrites thought to derive from deeper within the same parent body as acapulcoites
• Lunaite – a meteorite that originated from the moon (synonym of Lunar meteorite). Compare Category:Meteorites found on bodies other than Earth.
• Lunar meteorite – a meteorite that originated from the Moon (synonym of Lunaite). Compare Category:Meteorites found on bodies other than Earth.

M

• Main group pallasite – a pallasite belonging to the main group.
• Main mass – the largest/heaviest piece of a fragmented meteorite, typically found in a strewn field.
• Magmatic – igneous, that is, solidified magma or produced by magma
• Magmatic meteorite
• Magnetic – a characteristic of a meteorite that is attracted to a magnet.
• Martian meteorite – a meteorite that originated from Mars. Compare Category:Meteorites found on bodies other than Earth.
• Maskelynite – a natural glas found in meteorites.
• Matrix – the mineral assemblage surrounding chondrules.
• Mesosiderite – a grouping of stony-iron meteorite that are breccias.
• Meteor – an object passing through Earth's atmosphere emitting light.
• Meteoric iron – a native metal found in meteorites and a mixture of different mineral phases. Compare telluric iron.
• Meteoroid – a natural object in space no larger than 1 meter.
• Meteorite – a rock found on the Earth's surface that did not form on Earth.
• Meteorite Observation and Recovery Program – a scientific program that was centered in Canada.
• Meteoriticist – a scientist working on meteorites.
• Meteoritics – the science of meteorites.
• MORP – abbreviation for Meteorite Observation and Recovery Program.
• Micrometeorite – microscopic meteorites derived from Cosmic dust.

N

• Nakhlite – a group of Martian meteorites
• Neumann lines (or Neumann bands) – a pattern of fine parallel lines seen in some iron meteorites, thought to be due to impact events on the parent body
• Nonmagmatic meteorite – (deprecated) iron meteorites that were thought to have not formed by igneous processes.
• Northwest Africa – a popular meteorite find location.
• NWA – abbreviation of northwest Africa.

O

• O – usually refers to ordinary chondrite
• Observed fall – a meteorite that was seen when it fell to Earth.
• Octahedrite – the most common structural class of iron meteorites.
• Ordinary chondrite – a chondrite meteorite, where 'ordinary' means that it is the most common found
• Oriented – e.g. Photo: An oriented specimen of the <name> meteorite.

P

• PAC – abbreviation for primitive achondrite.
• Pallasite
• Panspermia – the hypothesis that life could reach other planets by the means of meteorites and/or comets.
• Parent body
• Petrologic type
• Pitts grouplet – a grouplet of meteorites that is part of the IAB meteorites
• Planetary achondrite – an achondrite that was differentiated on a planet and not a planetesimal or asteroid (See asteroidal achondrite).
• Plessite – a fine grained intergrowth found in meteoric iron consisting of kamacite, taenite and tetrataenite lamella.
• Presolar grains
• Primitive meteorite
• Primitive achondrite – a meteorite that has similarities with achondrites and chondrites.
• Pristine – extent of a meteorite shock stage and weathering.
• Protoplanetary disk – a cicumstellar disk from which all solids in the Solar System formed.
• Pyroxene pallasite grouplet

Q

• QUE – abbreviation for Queen Alexandra Range.
• Queen Alexandra Range – a mountain range in eastern Antarctica where many meteorites are found.

R

Regmaglypts on Sikhote Alin

• Regmaglypts – thumb print sized indentations in the surface of larger meteorites formed by ablation as the meteorite passes through a planet's atmosphere, probably caused by vortices of hot gas.
• Refractory elements – chemical elements that have high boiling and condensation temperatures.
• Rose-Tschermak-Brezina classification – a classification developed by Gustav Rose, Gustav Tschermak and Aristides Brezina.
• Rumuruti chondrite – a group of chondrites.

S

• Shergottite
• Shock stage
• Shock metamorphism
• Siderite – the old term for iron meteorite.
• Siderolite – the old term for stony-iron meteorites.
• SNC – abbreviation for shergottite, nakhlite and chassignite, the three martian meteorites.
• Solar nebula – a synonym of the protoplanetary disk.
• Spectral class –
• Stony meteorite – a meteorite composed mostly of silicates.
• Stony-iron meteorite – a meteorite that is a mixture of meteoric iron and silicates.
• Strewn field – a field of fragments from one meteorite fall.
• Structural class – a subdivision of iron meteorites in ataxites, hexahedrites and octahedrites.

T

• Taenite – a native metal (mineral) found in meteorites.
• Tamdakht
• Tektite - glassy terrestrial debris created by meteorite impacts.
• Total known weight (TKW) – total known mass of a meteorite.
• Trio – a grouping of three meteorites that share similar characteristics (see Grouplet).
• Tunguska event – an air burst of a meteorite that caused major destruction.
• Type – subdivision of meteorites. Loosely defined. Usually refers to chondrite, achondrite and sometimes primitive achondrite.

U

• Udei Station grouplet – a grouplet of meteorites that is part of the IAB meteorites.
• Ungrouped – a meteorite that has not been assigned to a group or grouplet.
• Undifferentiated
• Ureilite

V

• Vesta – second largest asteroid in the asteroid belt and likely source of the HED meteorites.
• Volatile elements – are chemical elements that have low boiling and condensation temperatures.

W

• Weathering – the terrestrial alteration of a meteorite.
• Widmanstätten pattern – a fine interleaving of kamacite and taenite bands/ribbons found in octahedrite irons and some pallasites.
• Willamette meteorite - the largest meteorite discovered in North America, found in the Willamette Valley of Oregon.
• Winonaite - a type of primitive achondrite meteorite.
• Weston meteorite – a meteorite which fell to earth above the town of Weston, Connecticut on December 14, 1807.

Y

• YA – abbreviation for Yamato Mountains.
• Yamato Mountains – a group of mountains in Antarctica where many meteorites are found.