achondrite

About half of the achondrites come from the large asteroid 4 Vesta.

(2001) Cronusite, [Ca.sub.0.2][([H.sub.2]O).sub.2][CrS.sub.2], a new mineral from the Norton County enstatite achondrite. Zapiski Vserossiyskogo Mineralogicheskogo Obshchestva 130(3), 29-36.

A few meteorites, the achondrites, contain only traces of nickel iron and therefore will not attract a magnet or feel unusually heavy.

Stones are further subdivided into chondrites and achondrites. Chondritic meteorites come in many varieties, including ordinary chondrites (comprising about 85 percent or more of falls), carbonaceous chondrites, enstatite chondrites, and rumuruti chondrites.

Known as basaltic achondrites, the group accounts for only 6 percent of terrestrial meteorites.

They compared these to meteorite samples, particularly enstatite chondrites and another type called enstatite achondrites. The measurements were done at the Swiss Federal Institute of Technology of Zurich in Switzerland.

Spectra of this rock, the third largest asteroid, have revealed that it is the only known parent of a class of meteorites called basaltic achondrites. This class accounts for 6 percent of all meteorites that fall to Earth.

Last year he and graduate student Shui Xu turned up the missing links between the large basalt-covered asteroid 4 Vesta and a group of unusual falls called basaltic achondrites. Vesta was already known to be a unique spectral match to the meteorites, but it orbits too far inside the 3:1 Jovian resonance and has too large an escape velocity to be considered the meteorites' direct source.

Ground-based observations indicate that Vesta represents the only known parent of a class of stony meteorites called basaltic achondrites. Researchers believe that some pieces chipped from Vesta by collisions with other asteroids ultimately fall to Earth as meteorites of this type.

Consider the meteorite class called basaltic achondrites, which make up about 6 percent of all meteorites recovered on Earth and which formed from once-molten material that originated on or under the surface of a small body.