Achondrites pallasites

Until recently, it was generally believed that the chondrites, which consist of relatively unaltered nebular material and thus are primitive objects, accreted early, whereas the differentiated meteorites (achondrites, irons, pallasites), which have had a history of melting... 

Irons are mostly fragments of asteroid cores. As with achondrites, their compositional variations reflect differences in parent body chemistry as well as changes wrought by crystallization. Pallasites may represent samples of core-mantle boundaries, and meso-siderites indicate poorly understood mixing of crust and core materials, probably by impact. 

Differentiated (planetary) Achondrites Angrites Aubrites Brachinites HED meteorites Eucrites Howardites Diogenites Ureilites Stony-irons Pallasites... 

Goodrich C. A. and Righter K. (2000) Petrology of unique achondrite Queen Alexandra Range 93148 a piece of the pallasite (howardite-eucrite-diogenite ) parent body Meteorit. Planet. Sci. 35, 521—535. 

Meteorites can be classified into stony, stony iron and iron. The most common meteorites are chondrites which are stony. Radiometric dating indicate an age of about 4.5x10 years. Achondrites are also stony but they are considered differentiated or reprocessed matter. They are formed by melting and recrystallization on or within meteorite parent bodies. Pallasites are stony iron meteorites composed of olivine enclosed in metal. 

---