ablate / abla=
tion: describes the removal of meteoritic surface
material,
usually due to ram-pressure heating and melting upon atmospheric entry
achondrite:
a meteorite that is not a chondrite. Some classification schemes lim=
it
achondrites to stony meteorites
aerolite:
former name for a stony meteorite
anion (“ann-eye-un”): an atom or radical (group of atoms) tha=
t has
an excess of one or more electrons
and therefore has a negative electric charge
anomalous:
describes a meteorite that has properties that are unusual for its classifi=
cation
ataxite=
:
an iron meteorite that does not display a Widmanstätten pattern when
polished and etched
basalt (“ba-salt”): fine-grained igneous rock formed by rapid
cooling of low-density lava
breccia (“bresh-see-ya”): a stone t=
hat
consists mostly of clasts
bronzite:
a pyroxene with about twice as much magnesium as iron
calcium-aluminum-rich inclusion (=
CAI):
a light-colored inclusion found in carbonaceous
chondrites
caliche (“ka-lee-chee”): carbonate coating or adhesion to meteorites c=
aused
by soil and moisture on Earth
carbonaceous chondrite=
: a class of chondrite that contains carbonates,
indicating that it was formed in an environment that supported liquid water=
cation (“cat-eye-un”):
an atom or radical (group of atoms) that has a deficit of one or more elect=
rons
and therefore has a positive electric charge
chondrite:
an undifferentiated meteorite that has a composition similar to the
non-volatile components
of the Sun; most contain chondrules
chondrule:
a spherical inclusion (round grain) formed from droplets of material that
solidified
in the early Solar System
chromite:
an iron-chromium oxide mineral: FeCr2O4
clan: see classification
class: see classification
classification:
organization scheme for meteorites;
from most general to most specific: division,
class, clan, group, subgroup
clast:
a fragment of stone contained in a larger stone specimen
crusted:
indicates that a specimen has a full or partial fusion crust; one or
more layers of crust
can partially ablate resulting in secondary and tertiary fusion crust
differentiated:
describes a meteorite that originated from an asteroid that has undergone
differentiation:
the process of separating heavier materials from lighter materials in an
astronomical body due to internal heating
division: see classification
end slice:
a slice where one side is the outside of the meteorite; sometimes called an=
endcut
endcut: see end-slice
enstatite:
magnesium-rich pyroxene: MgSiO3; also refers to a class o=
f chondrites
containing
elevated percentages of enstatite
equilibrated:
indicates that the original mineral components of a meteorite have been
significantly altered (or blended) due to temperature and pressure
etched:
a process where an iron or stony-iron meteorite has been polished and a weak
acid applied
to expose the Widmanstätten pattern
fall:
one or more meteorites discovered as a result of a witnessed or documented
impact event
fayalite:
iron-rich olivine: Fe2SiO4
feldspathic:
containing potassium-, sodium-, or calcium-aluminum silicates
ferrosilite:
iron-rich pyroxene: FeSiO3
find:
one or more related meteorites discovered without benefit of a
witnessed/documented impact event
forsterite:
magnesium-rich olivine: Mg2SiO4
fragment:
a broken-off piece of an individual
friable:
describes a specimen that is prone to crumbling
full slice:
a complete slice of an individual
fusion crust:
full or partial coating on a meteorite due to ram pressure heating
as it passes through Earth’s atmosphere
group: see classification
hammer:
a fall that impacted a person, animal, or man-made object
hypersthene:
a pyroxene with roughly equal amounts of magnesium and iron
imbricated:
describes overlapping features within a meteorite
impact sediment:
sedimentary Earth rock containing evidence of meteorite impact
impactite:
Earth rock created or modified by meteorite impact on Earth
individual:
a complete meteorite
irons:
meteorites that are all or nearly all metal
kakangariite:
an extremely rare class/group of chondrites
kamacite:
an alloy consisting of iron mixed with 5% to 12% nickel
lamellae (singular: lamella): the bands or ribbons that compr=
ise
a Widmanstätten pattern
main mass:
the significantly largest specimen of a named meteorite
maskelynite:
a glassy material with a composition similar to plagioclase
mesosiderite:
a stony-iron meteorite with a roughly equal mix of stone and metal
metachondrite<=
/span>:
a chondrite that features obliterated chondrules due to
temperature and pressure
meteor:
a meteoroid that enters Earth’s atmosphere and glows due to friction=
al
heating
meteorite:
a meteoroid or piece of a meteoroid that survives its trip through t=
he
atmosphere
meteoriticist<=
/span>:
a scientist who studies meteorites
meteoritics:
the study of meteorites
meteoroid:
a small solid solar system body
meteor-wrong:
a terrestrial or man-made specimen that could be mistaken for a meteorite
monomict:
the clasts in a breccia consist of the same kind of stone
olivine:
a magnesium iron silicate: (Mg+2, Fe+2)2SiO4
oriented:
describes a crusted meteorite that did not tumble during flight,
resulting in visible flow lines in its fusion crust
oxide:
see shale
oxidite:
see shale
paired:
indicates that a named meteorite may be another specimen of a previously-named meteorite
pallasite:
a stony-iron meteorite with olivine crystals embedded in a metal mat=
rix
part slice:
a part of a full slice
peridot:
gem-quality olivine
plagioclase:
a sodium-aluminum silicate (NaAlSi3O8), calcium-alumi=
num
silicate (CaAlSi3O8),
or mixture
plessite:
a fine-grained mixture of kamacite and taenite
polymict:
the clasts in a breccia consist of more than one type of stone
primitive achondrite
provisional:
describes a meteorite that has been named and classified,
but not officially approved by the Meteoritical Society
pseudo-meteorite:
a man-made specimen designed to resemble a meteorite
pyroxene:
a chain magnesium iron silicate: (Mg+2, Fe+2)SiO=
3
regmaglypts:
depressions on the exterior of a meteorite where more volatile areas have <=
b>ablated;
sometimes called thumbprints
regolith:
loose, fragmental material on a planetary or asteroidal surface
relict: indicates a meteoritic structure (such as a
chondrule) that has survived equilibration
or other destructive process
rumurutiite:
a rare class/group of chondrites
ruster<=
/b>:
a metallic specimen that is prone to oxidation
shale:
describes an iron meteorite that has completely oxidized;
the descriptor oxide or oxi=
dite
may also be used
shock:
amount of stress applied to a specimen due to an impactor
siderite:
former name for mixtures of iron and nickel that form the bulk of iron
(and some stony-iron) meteorites
siderolite:
former name for a stony-iron meteorite
silicate:
any mineral consisting of tetrahedral anions containing silicon atoms
bonded to four oxygen atoms
skeleton:
a pallasite where the mineral component (olivine) has weather=
ed
away leaving the metal behind
specimen:
an item of meteoritic (or meteorite-related) origin
stony:
describes meteorites that are mostly comprised of stone or mineral (i.e., non-metal)
stony-iron
strewn field:
the area that encompasses a fall or find
subgroup: see classification
taenite:
an alloy consisting of iron mixed with 20% to 65% nickel
tektite:
a specimen of glassy terrestrial debris from a meteorite impact
thin section:
a very thin slice of a specimen that can be analyzed via its
transmission of polarized light
Thomson structure: see Widmanstätten
pattern
thumbprints: see regmaglypts
total known weight (TKW):
the sum of the weights of all specimens of a named meteorite
troilite:
an iron sulfide (FeS) mineral more common in
meteorites than on Earth
twinning:
describes adjacent crystals that symmetrically share some part of their cry=
stal
structure
type specimen:
the (usually) first meteorite found that represents a class or sub-c=
lass
of meteorites
unclassified:
a specimen that has not been submitted to a recognized meteorite testing
facility
undifferentiated:
a meteorite that originated from an asteroid that was not large enough
to undergo differentiation
unequilibrated:
indicates that the original mineral components of a meteorite have retained=
their structural integrity
ungrouped:
describes a meteorite that does not belong to a current group or =
subgroup
weathering:
deterioration or other changes to a meteorite due to environmental factors =
on
Earth
Widmanstätten pattern<=
span
style=3D'font-size:12.0pt;line-height:115%;font-family:"Times New Roman",se=
rif'>:
a distinctive pattern due to the coexistence of kamacite and taenite crysta=
ls
in many iron meteorites; also known as Thomson
structure
window:
the portion of the interior of an individual that is visible after a
small end-slice has been removed
xenolith:
a specimen that contains two distinct types of stone
X-ray fluorescence (XRF):
a technology that measures the elemental composition of a sample
that can be helpful in meteorite identification
Meteoritics Glossary