Meteorites Meteorites An Achondrite is a stony meteorite that is made of material similar to terrestrial basalts or plutonic rocks. Compared to the chondrites, they have all been differentiated and reprocessed to a lesser or greater degree due to melting and recrystallization on or within meteorite parent bodies. As a result, achondrites have distinct textures and mineralogies indicative of igneous processes. ...more on Wikipedia about "Achondrite"
ALH84001 (Allen Hills, 1984 #001) is a meteorite found in Allen Hills, Antarctica in December 1984 by a team of US meteorite hunters from the ANSMET project. Like other members of the group of SNCs (shergottite, nakhlite, chassignite), ALH84001 is almost certainly from Mars, shocked and broken by one or more meteorite impacts some 3.6 billion years ago, and blasted off of the surface of Mars in a separate impact about 15 million years ago. ...more on Wikipedia about "ALH84001"
Amphoterite is an obsolete term used to describe chondritic meteorites that are now classified as LL (Low Iron and Low total metal content) types. Most of the metal in these types of meteorites actually comes from the minerals (e.g. olivine) in the meteorite rather than free metal, as is found in most meteorites. Free metallic iron will form between 0.3% and 3.0% of the meteorite, and with a total iron content of 20% give or take a couple of percentage points. There will be a number after the LL in a meteorites classification type, e.g. LL3, LL5, LL6. (Types range from 3 to 7) The number indicates the amount of alteration suffered by the chondrules in the meteorite. A chondrule is a small mineral ball generally 0.1mm to 4mm in diameter. An LL3 type is pristine with perfectly discernable chondrules, an LL7 type has been melted or altered by pressure or other force to almost completely obliterate the round chondrules. ...more on Wikipedia about "Amphoterite"
Ann Elizabeth Hodges ( 1923 - 1972) of Sylacauga, Alabama is the only person of record to have been hit by a meteorite. On November 30, 1954, she was napping on her living room couch when a grapefruit-sized rock from space crashed through the roof of her house. It bounced off her large wooden console radio, destroying it, and struck her on the arm and hip. She was badly bruised but able to walk. ...more on Wikipedia about "Ann Hodges"
ANSMET (ANtarctic Search for METeorites) is a program funded by the Office of Polar Programs of the National Science Foundation that looks for meteorites in the Transantarctic Mountains. ...more on Wikipedia about "ANSMET"
Ataxites are a class of iron meteorites. They are composed mainly of the alloy taenite, and also contain plessite, troilite, and microscopic lamellae of kamacite. They have no visible Widmanstätten pattern. Ataxites are the most nickel-rich meteorites known (usually contain over 18% nickel). ...more on Wikipedia about "Ataxite"
Ca-Al-rich inclusions (CAIs) are centimeter sized light-coloured calcium and aluminium rich inclusions found in carbonaceous chondrites. CAIs consists of high temperature minerals and are among the first solids which condensed from the cooling protoplanetary disk. Using lead isotopic data determined on CAIs an age of 4567.2±0.6 million years can be calculated which can be interpreted as the beginning of the formation of the planetary system. However, due to possible disturbations of the Pb isotopic system within the CAIs this age is possibly only a lower limit of the true age. Also an age of 4571 Ma for CAIs has been given, based on Mn- Cr and Mg- Al isotopic data. ...more on Wikipedia about "Ca-Al-rich inclusions"
The Canyon Diablo meteorite impacted at Barringer Crater, Arizona and is known from fragments collected around the crater and nearby Canyon Diablo which lies about 3 to 4 miles west of the crater. The meteorite is an iron octahedrite which fell between 20,000 and 40,000 years ago. The meteorite has been known and collected since the mid 1800s and was known and used by pre-historic Native Americans. The meteorite and the Barringer Crater were the center of the long disputed theories of origin through the late 19th and first half of the 20th centuries. ...more on Wikipedia about "Canyon Diablo meteorite"
A carbonaceous chondrite or a C-type chondrite is a type of chondritic meteorite which contains high levels of water and organic compounds, representing only a small proportion (~5%) of known meteorites. Their bulk composition is mainly silicates, oxides and sulfides, whilst the minerals olivine and serpentine are characteristic. The presence of volatile organic chemicals and water indicates that they have not undergone significant heating (>200°C) since they formed, so their composition is considered to be representative of the solar nebula from which the solar system condensed. ...more on Wikipedia about "Carbonaceous chondrite"
Most meteorites are full of millimeter-sized silicate spherules which are called chondrules (from Greek chondros, grain), suspended in a fine-grained matrix which includes cosmic dust grains and chondrule fragments. Meteorites which contain chondrules are called chondrites or chondritic meteorites. They can consist of up to 80% chondrules. ...more on Wikipedia about "Chondrule"
Diogenites are achondritic stony meteorites that originate from deep within the crust of the asteroid 4 Vesta, and as such are part of the HED meteorite group. There are about 40 distinct members known. ...more on Wikipedia about "Diogenite"
Eucrites are achondritic stony meteorites that originate from the surface of the asteroid 4 Vesta, and as such are part of the HED meteorite group. They are the most common achondrite group with well over 100 distinct finds at present. ...more on Wikipedia about "Eucrite"
The H type ordinary chondrites are the most common type of meteorite, accounting for approximately 40% of all those catalogued, 46% of the oridnary chondrites, and 44% of the chondrites [1]. ...more on Wikipedia about "H chondrite"
Hapkeite is a mineral discovered in a meteorite found in 2000 in the Saudi peninsula of Oman, which originated from Earth's moon. Hapkeite's composition is of silicon and iron, and is similar to other silicon-iron minerals found on Earth. On the moon, the impact is thought to have heated and melted the rock. The metallic vapour is redeposited on rock grains as tiny beads in a glassy coating. Hapkeite is named after University of Pittsburgh scientist Bruce Hapke, who predicted the presence and importance of vapour-deposited coatings on lunar soil grains about 30 years ago. Due to its 1:2 composition of silicon-iron, it was given the chemical formula Fe2 Si. ...more on Wikipedia about "Hapkeite"
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Heat Shield Rock is a basketball-sized iron-nickel meteorite found on Mars by the Mars rover Opportunity in January 2005. The meteorite was formally named Meridiani Planum by the Meteoritical Society in October, 2005 (meteorites are always named after the place where they were found). ...more on Wikipedia about "Heat Shield Rock"
The HED meteorites are a grouping of three achondrite meteorite types, the: ...more on Wikipedia about "HED meteorite"
Hexahedrites are a type of iron meteorite. ...more on Wikipedia about "Hexahedrite"
Howardites are achondritic stony meteorites that originate from the surface of the asteroid 4 Vesta, and as such are part of the HED meteorite group. There are about 50 distinct members known. ...more on Wikipedia about "Howardite"
The iron meteorites of the IIE chemical type are octahedrites of various coarseness, most of which contain numerous inclusions of recrystallized stony silicates. ...more on Wikipedia about "IIE iron meteorite"
Impactite is rock created nearly instantaneously by the impact of a meteorite on sand (e.g., the Wabar impact site in the Empty Quarter of Saudi Arabia) or soil on Earth. At the Wabar site it has the appearance of chunks of coarsely laminar, bleached-white sandstone weighing up to 10 kg. The crude lamination is perpendicular to the propagation vector of the impact shockwave. Often the impactite is coated with material (sometimes called simply "glass") from the ejected "jet" of the impact process. At Wabar, this "glass" consists of about 90% local sand and 10% iron- nickel meteorite, and may have originally been at temperatures in excess of 10,000 °C. ...more on Wikipedia about "Impactite"
Iron meteorites consist overwhelmingly of nickel- iron alloys. ...more on Wikipedia about "Iron meteorite"
Kamacite is a mineral. It is an alloy of iron and nickel, usually in the proportions of 90:10 to 95:5 although impurities such as cobalt or carbon may be present. On Earth, it occurs naturally only in meteorites. It has a metallic lustre, is grey and has no clear cleavage although the structure is isometric-hexoctahedral. Its density is around 8 g/cm³ and its hardness is 4 on the Mohs scale. It is also sometimes called balkeneisen. ...more on Wikipedia about "Kamacite"
The L type ordinary chondrites are the second-most common type of meteorite, accounting for approximately 35% of all those catalogued, and 40% of the oridnary chondrites [1]. ...more on Wikipedia about "L chondrite"
This is a list of lunar meteorites. That is, meteorites that have been identified as having originated on the Moon. As of 2004 there were only 36 known lunar meteorites. ...more on Wikipedia about "List of Lunar meteorites"
Lonsdaleite is a hexagonal allotrope of the carbon allotrope diamond, believed to form when meteoric graphite falls to Earth. The great heat and stress of the impact transforms the graphite into diamond, but retains graphite's hexagonal crystal lattice. Lonsdaleite was first identified from the Canyon Diablo meteorite at Barringer Crater (also known as Meteor Crater) in Arizona. It was first discovered in 1967. Lonsdaleite occurs as microscopic crystals associated with diamond in the Canyon Diablo meteorite; Kenna meteorite, New Mexico; and Allan Hills (ALH) 77283, Victoria Land, Antarctica meteorite. It has also been reported from the Tunguska impact site, Russia. ...more on Wikipedia about "Lonsdaleite"
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