achondrite


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achondrite

(ay-kon -drÿt) Any of a class of stony meteorites that lack the characteristic chondrules of the chondrites. They are usually more coarsely crystallized than the chondritic stones and are more similar chemically and mineralogically to some terrestrial rocks. They contain very little iron and nickel. Achondrites resemble volcanic rocks and are thought to be products of large-scale melting on their parent bodies, i.e. they are differentiated or reprocessed matter. See also HED meteorites; SNC meteorites.

achondrite

[¦ā′kän‚drīt]
(geology)
A stony meteorite that contains no chondrules.
References in periodicals archive ?
Not surprisingly, extremely rare lunar and Martian achondrites can sell for thousands of dollars per gram.
Achondrites (which lack chondrules) are prized by scientists and collectors alike because they come from the Moon, Mars, the asteroid Vesta, and other geologically differentiated bodies.
Achondrites are usually the most expensive because of their rarity and place of origin.
Basaltic achondrites lack the rounded particles, or chondrules, found inside most stony meteorites.
Only one known asteroid, 4 Vesta, has a surface composition similar to that of basaltic achondrites, researchers showed in the 1970s.
Binzel and Xu conclude that 4 Vesta is indeed the parent body of most basaltic achondrites. They reported their work last week in Munich, Germany, at a meeting of the American Astronomical Society.
That mineral also predominates in a group of meteorites called enstatite achondrites. Gaffey's team believes these meteorites represent fragments of the kilometer-size asteroid they studied.
Researchers had previously suspected that enstatite achondrites came from the Hungaria region, but they discounted the idea because the surfaces of meteorites falling to Earth directly from this locale would have been bombarded by cosmic rays for tens of millions of years.