Achondrite
An achondrite is a stony meteorite that has been melted, so it has no chondrules.
The word achondrite means "without chondrules". These stony meteorites come from bodies that grew hot enough to melt, either partly or completely. Melting destroyed the original chondrules and let the rock separate into layers, much as Earth formed a metal core, a rocky mantle and a crust. Achondrites are pieces of those mantles and crusts.
They matter because they show how small worlds evolved. Many come from large asteroids, and the HED group (howardites, eucrites and diogenites) is thought to come from the asteroid Vesta. A few achondrites come from the Moon and Mars, giving scientists samples of other worlds without needing a spacecraft to bring them back. One classic achondrite is Juvinas, a eucrite that fell in France on 15 June 1821. It looks much like a basalt, a common volcanic rock on Earth.
Achondrites can be hard to recognise because they resemble Earth rocks and often contain little metal, so they may not attract a magnet. A fresh fusion crust, which is sometimes glossy, is a helpful clue, but laboratory tests are needed to be sure.
Related terms
Level: Explorer Ages 10 and up