The Polished Face of the Djoua 001 Aubrite

A 3.3kg half stone, my first aubrite meteorite, a rare and special stone.

Their igneous origin differentiates them from other enstatites, and it means that they originated from an asteroid. Aubrites are mainly composed of large white orthopyroxene crystals rich in Mg or enstatite. Around this matrix, they feature minor phases of olivine, nickel-iron metal and troilite, denoting a magmatic formation under ground on their parent body under extremely reducing (oxygen-free) conditions. The great brecciation of most aubrites gives evidence of a violent history in their parent body… but this one is unbrecciated (only 20% of Aubrites are unbrecciated).

“The Aubrites are a fascinating group of meteorites, because they are rocks of extremes. Aubrites must have formed in a very unique part of the solar nebula, possibly within 1 AU of the Sun (a near Earth orbit). Their ingredients are clearly of igneous origin and formed by melting and fractional crystallization, possibly of a magma ocean. Age dates suggest that the aubrites formed very early in the history of the solar system, within a few Ma of CAI formation, and that the heat sources for heating and melting of their parent bodies were, most likely, short-lived radionuclides such as 26Al and, perhaps, 60Fe.” — Geochemistry 2010

Comparisons of Aubrite spectra to the spectra of asteroids have revealed striking similarities between the Aubrite group and the E-type asteroids of the Nysa family. A small asteroid close to the Earth, 3103 Eger, is the putative source body of the Aubrites. Wikipedia: “3103 Eger is the only asteroid besides 4 Vesta identified as the parent body for specific meteorites. 4 Vesta is the parent body for HED meteorites, while 3103 Eger is the parent body for Aubrite meteorites.” The other prospect is 2867 Steins, the target of the Rosetta Mission. More 3D analysis from NASA and compared to Mercury.

“Aubrites have the highest cosmic-ray exposure ages of any stony meteorites, ranging up to 120 million years. A study of isotopic compositions of the elements samarium and gadolinium suggests that this exposure happened in the interval between leaving the aubrite parent body and arriving on Earth, rather than during the time the rock was on the surface of the parent body. However, this conclusion poses challenges to models of the orbital dynamics of these meteorites and to the suggestion from other research that certain achondrites experience space erosion up to 5 mm every million years.” — DavidDarling

Djoua 001 was found in 2021 in Algeria and the “interiors are overall mottled beige and gray in color with sporadic small dark and rusty spots. Rare tiny grains of fresh metal are visible on polished pieces. Some large whitish grains (enstatite) are up to 1.5 cm across.”