Stony-iron meteorites or siderolites are meteorites that consist of nearly equal parts of meteoric iron and silicates. This distinguishes them from the stony meteorites, that are mostly silicate, and the iron meteorites, that are mostly meteoric iron.
Stony-iron meteorites are all differentiated, meaning that they show signs of alteration. They are therefore achondrites.
The stony-irons are divided into mesosiderites and pallasites. Pallasites have a matrix of meteoric iron with embedded silicates (most of it olivine) Mesosiderites are breccias which show signs of metamorphism.