I just obtained a bit of Bennu/Ryugu (or a parent body), in the form of a fresh meteorite.
This Oued Chebeika 002 (OC 002) meteorite was found in Morocco in 2024, the purest find of an incredibly rare category of carbonaceous chondrite (CI1), the most primitive material that best resembles the sediment of our solar nebula in its early formation. It is fragile and friable, and little exists on Earth. From analysis of its remnant magnetism, it appears that the parent body formed in the first 5 million years of our solar system (4.56 billion years ago) and went through aqueous alteration in a brine, forming clays and mineral salts.
It consists of fine-grained black phyllosilicates with abundant magnetite and visible iron sulfide grains. The recent studies on the returned asteroid samples from Ryugu and Bennu are an identical match to this meteorite on mineral composition and grain sizes. The closest match is to Ryugu Chamber A particles.
It is rich in amino acids, and all of the nucleobases that make our DNA. It is the subject of intense study, as it seeded Earth with the building blocks of life, which formed abiotically in ice out past the asteroid belt.
From a 2025 LPSC paper MINERALOGY OF OUED CHEBEIKA 002: A TRUE CI1 CHONDRITE:
"The recent studies on the returned asteroid samples, Ryugu and Bennu, clearly showed that they are CI chondritic materials, and thus, the importance of CI chondrites has been rediscovered."
"The modal mineralogy and grain sizes of the constituent minerals are almost identical to those of Ryugu samples and CI chondrites. The mineral compositions of the constituent minerals are basically identical to those observed in Ryugu and CI chondrites."
"OC 002 is a true CI1 chondrite because it essentially lacks olivine and pyroxene even at a few µm scale."
"The material most similar to OC 002 is Ryugu Chamber A particles, even considering the effect of terrestrial weathering. OC 002 is a desert find, yet it is surprisingly fresh and comparable to Ryugu samples. It still contains abundant submicron Fe-Ni sulfide and is almost free of terrestrial weathering products such as Ca sulfate, although they are common in old CI chondrite fall samples."
From another 2025 LPSC paper: Oued Chebeika 002: expanding the CI chondrite inventory:
"CI1 chondrites are important material in cosmochemistry. Their chemical composition matches that of the solar photosphere within 10 % for about 30 elements, whereas all other chondritic groups are significantly fractionated relative to CI chondrites. The CI chemical composition is thus considered as the best approximation of that of the early Solar System.
Partly because their friable nature makes them unlikely to survive atmospheric entry, CI1 chondrites are exceedingly rare, with only 5 meteorites in collections"
"Like samples returned from asteroid Ryugu, Oued Chebeika 002 does not contain products attributed to terrestrial alteration in the CI1 falls, such as sulfates. As such, Oued Chebeika 002 may represent the freshest available CI1 material besides what was returned from asteroids Ryugu and Bennu."
From a Nobel Gas analysis paper:
"Carbonaceous chondrites of CI type are among the most primitive materials found in the solar system with chemical composition very close to the solar one and are crucial to understand the delivery of volatile elements to planets"
And the Met Bull CI1 classification:
"carbonaceous chondrite: A major class of chondrites that mostly have Mg/Si ratios near the solar value and oxygen isotope compositions that plot below the terrestrial fractionation line.
"CI group: The Ivuna (CI) chemical group of carbonaceous chondrites, distinguished by the complete absence of chondrules and refractory inclusions, and high degree of hydration."
"type 1: Designates chondrites which have experienced a high degree of aqueous alteration. Most primary minerals have been replaced by secondary phases and chondrules are generally absent."
"X-ray diffraction of a powdered 10 mg sample (D. Borschneck, CEREGE) confirms the mineralogy determined by optical and backscattered electron observations, with the presence of the following minerals: clay minerals, magnetite, pyrrhotite, and minor pentlandite, dolomite, and apatite. X-ray diffraction of the clay fraction indicates smectite and serpentine. Magnetic susceptibility close to the value measured for Ryugu material. This magnetic susceptibility value indicates a magnetite content of about 10 wt%."
"The JAXA Hayabusa 2 mission returned 5.4 g of material from the C-type asteroid Ryugu. The Mn-Cr ages of dolomite in the returned samples indicate that Ryugu’s parent body experienced aqueous alteration sometimes between <1.8 and 6.8 Myr after CAI formation. Because this time range overlaps with the lifetime of the solar nebula, we investigate the possibility that magnetite and pyrrhotite, which are aqueous alteration products found in Ryugu samples, acquired a remanent magnetization reflecting the nebula field intensity. We analyze the intrinsic magnetic properties and paleomagnetic record of three Ryugu samples of 0.82, 0.97 and 21.87 mg. None of the samples exhibit a stable natural remanent magnetization. This indicates that the aqueous alteration of Ryugu’s parent body took place either in a field of a few µT, or in a very weak to null field. In the former scenario, the solar nebula field is the most likely magnetizing field, implying that aqueous alteration occurred before its dissipation, i.e., before ∼5 Myr after CAI formation. In the latter scenario, aqueous alteration must have occurred either after the dissipation of the nebula, or at an earlier epoch and a large heliocentric distance (> 5 au). The similarities between Ryugu samples and CI chondrites favor this second hypothesis."
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