Pure* magnesium end-member (Mg2SiO4) of the olivine solid solution series and an important mineral in meteorites. When magnesium (Mg) is completely substituted by iron, it yields the the pure Fe-olivine end member, fayalite (Fe2SiO4). The various Fe and Mg substitutions between these two end-members are described based on their forsteritic (Fo) Chondrites are the most common meteorites accounting for ~84% of falls. Chondrites are comprised mostly of Fe- and Mg-bearing silicate minerals (found in both chondrules and fine grained matrix), reduced Fe/Ni metal (found in various states like large blebs, small grains and/or even chondrule rims), and various refractory inclusions (such or F-Chondrites are presently only known as inclusions in other meteorites and described by certain lithologies of the Cumberland Falls Aubrites are named for the Aubres meteorite that fell in 1836 near Nyons, France. They are an evolved achondrite that is Ca-poor and composed mainly of enstatite (En100) and diopside (En50Wo50) with minor amounts of olivine (Fa0) and traces of plagioclase (An2-8). They contain large white crystals of enstatite as. They are thought to have derived from a small and primitive asteroid of F chondritic composition that collided with the aubrite The body from which a meteorite or meteoroid was derived prior to its ejection. Some parent bodies were destroyed early in the formation of our Solar System, while others like the asteroid 4-Vesta and Mars are still observable today. shortly after their formation in the early The Sun and set of objects orbiting around it including planets and their moons and rings, asteroids, comets, and meteoroids.. Mineralogical, they consist primarily of forsterite. Forsterite chondrites are intermediate between the H and E chondrites in terms of their chemical makeup. To date, no complete meteorites of this group have been found, and therefore this class should be considered hypothetical. NWA 7135 and El Médano 301 are both Modifying term used to describe meteorites that are mineralogically and/or chemically unique and defy classification into the group or sub-group they most closely resemble. Some examples include Ungrouped Achondrite (achondrite-ung), Ungrouped Chondrite (chondrite-ung), Ungrouped Iron (iron-ung), and Ungrouped Carbonaceous (C-ung). chondrites purported to contain F-chondrite clasts.