Classification

The two large families are distinguished by the state of differentiation of the parent body:

 

Chondrites, undifferentiated meteorites, come from small asteroids which have not, or very little, melted and have kept their initial components. Thus the chondrules, globules of silicates and iron, are intact in the chondrites. These meteorites represent 91% of the classified meteorites.

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Differentiated meteorites , on the other hand, come from parent bodies large enough to differentiate, like the Earth, into a metallic core, a mantle and a crust. Thus, so-called achondrite meteorites come from a crust (6.5% of samples in world collections), while metallic meteorites  (2%) come from a mantle and so-called mixed meteorites (semi-stony/semi-ferrous - 0.5%) possibly from the mantle-core boundary or a mix of mantle-core materials. Among the so-called differentiated meteorites, there are also primitive achondrites, which come from a parent body which initiated its differentiation without completing it, and which therefore have characteristics close to chondrites as well as achondrites.

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This classification into two families is made on the criteria of petrography, i.e. texture and components, and chemistry of meteorites.

 

From these two large families derive the classes (chondrites, achondrites, mixed and metallic) and the groups, formed on complementary petrographic and chemical criteria, as well as mineralogical and isotopic criteria.