The best-known specimens come from meteorite falls and finds in Krasnoyarsk (Russia—the original pallasite described by Peter Pallas in 1772), Esquel (Argentina), Imilac (Chile), and Seymchan (Russia). This is a rare class of iron-stone meteorites (less than 1% of all finds) consisting of olivine crystals—often gem-quality and amber-green in color—embedded in a continuous metallic iron-nickel matrix. Their origin is generally attributed to the interface between the metallic core and the silicate mantle of a differentiated planetary body (asteroid) that was fragmented by impacts; they formed approximately 4.5 billion years ago, at the dawn of the Solar System. The slow cooling (a few degrees per million years) produces the characteristic Widmanstätten patterns in the metallic matrix, visible after cutting and acid etching. High density (4.5–5.0 g/cm³), strongly magnetic.

It is among the most sought-after materials by collectors and museums due to the rarity and aesthetic appeal of its polished sections, in which the translucent olivine stands out against the metal; gem-quality olivines are sometimes cut into jewelry as “extraterrestrial peridot”; of immense scientific value for the study of planetary differentiation. It requires storage in a dry environment to prevent oxidation of the metal.