# Glossary of meteoritics

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

## Contents

* 0–9
* A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
* References
* 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 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.
* ANSMET – the Antarctic Search for Meteorites is a 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.
* Aubrite – a class of achondrite meteorites composed primarily of the orthopyroxene enstatite

## B

* Basaltic achondrite – a grouping of basalt meteorites (HED meteorites + Angrite)
* Brachinite – either a primitive achondrite or an asteroidal achondrite
* Bolide – is an extremely bright meteor, especially one that explodes in the atmosphere

## 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 study of the chemical composition of the universe and its constituents, and the processes that produced those compositions.

## 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 do not 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.$^{:320}$ (It is, however, not a fossil).
* Fusion crust – a coating on meteorites that forms during their passage through the atmosphere.

## G

* Group – a collection of five or more meteorites sharing similar characteristics.
* Grouplet – a collection of fewer than five meteorites sharing similar characteristics.

## H

* Hammer Stone – a specific individual meteorite that has hit either a human, man-made object, and/or an animal.
* 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 meteorite
* Martian meteorite – a meteorite that originated from Mars. Compare Category:Meteorites found on bodies other than Earth.
* Maskelynite – a natural glass found in meteorites.
* Matrix – the mineral assemblage surrounding chondrules.
* Mesosiderite – a grouping of stony-iron meteorite that are breccias.
* Meteoric iron – a native metal found in meteorites and a mixture of different mineral phases. Compare telluric iron.
* Meteorite Observation and Recovery Program – a scientific program that was centered in Canada.
* Meteoriticist – a scientist working on meteorites, meteors, and meteoroids.
* Meteoritics – the science of meteorites, meteors, and meteoroids.
* 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.

## 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

## P

* PAC – abbreviation for primitive achondrite.
* Pallasite – a class of stony–iron meteorite.
* Panspermia – the hypothesis that life could reach other planets by the means of meteorites and/or comets.
* Parent body – the celestial body from which originates a meteorite or a class of meteorites.
* Petrologic type – a classification scheme that expresses the degree to which a meteorite has been affected by the secondary processes of thermal metamorphism and aqueous alteration on the parent asteroid.
* 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 – interstellar solid matter in the form of tiny solid grains from a time before the Sun was formed.
* Primitive meteorite
* Primitive achondrite – a meteorite that has similarities to achondrites and chondrites.
* Protoplanetary disk – a circumstellar disk from which all solids in the Solar System formed.
* Pyroxene pallasite grouplet

## R

* Regmaglypts – thumbprint-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.
* Rose-Tschermak-Brezina classification – a classification developed by Gustav Rose, Gustav Tschermak and Aristides Brezina.
* Rumuruti chondrite – a group of chondrites.

## S

* Shergottite – igneous rocks of mafic to ultramafic lithology, named after a meteorite that fell at Sherghati, India in 1865.
* Shock stage – a measure of the degree of fracturing of the matrix of a common chondrite meteorite.
* Shock metamorphism – the effects of shock-wave related deformation and heating during impact events.
* Siderite – the old term for iron meteorite.
* Siderolite – the old term for stony-iron meteorites.
* SNC – abbreviation for shergottite, nakhlite and chassignite, the three main types of Martian meteorite.
* 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.
* Superbolide – is a bolide that reaches an apparent magnitude of −17 or brighter, which is roughly 100 times brighter than the full moon. Recent examples of superbolides include the Sutter's Mill meteorite and the Chelyabinsk meteor.

## T

* Taenite – a native metal (mineral) found in meteorites.
* Tamdakht – a meteorite that fell near Ouarzazate, Morocco on 2008-12-20 producing a strewn field of approximately 25 km (16 mi) by 2 km (1.2 mi) and two small impact craters.
* Tektite – glassy terrestrial debris created by meteorite impacts.
* Thumbprinting – see regmaglypts
* Total known weight (TKW) – total known mass of a meteorite.
* Trio – a grouping of three meteorites that share similar characteristics (see Grouplet).
* 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

* 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.