NWA XXX Ordinary Chondrite Meteorite Individual, unclassified, 635.58g, Flight Oriented with Regmaglypts

Flight-oriented chondrite with pristine atmospheric entry features

This 635.58g ordinary chondrite individual preserves the classic geometry of atmospheric flight orientation. The forward-facing surface shows a smooth, continuous fusion crust interrupted by thermal contraction cracks that formed as the exterior cooled rapidly during deceleration. Regmaglypts -- thumbprint-like depressions sculpted by ablation -- cover the oriented surface, documenting differential melting as the meteorite maintained stable orientation through the atmosphere. The preservation extends to 99% of the specimen's surface, with minimal post-fall weathering obscuring the original entry features.

The specimen's magnetic response suggests possible L-group classification, though laboratory analysis has not been completed. The intact crust and oriented geometry make this a textbook example of controlled atmospheric entry, where aerodynamic forces kept one face consistently forward during descent.

Fusion crust and thermal features

The black glassy fusion crust formed at temperatures exceeding 1,600°C as atmospheric friction vaporized the meteorite's leading edge. Contraction cracks radiate across the crust where rapid cooling created tensile stress in the newly formed glass. These fractures often expose the lighter interior material, creating a network of contrast against the dark exterior. Secondary flow features -- areas where molten material streamed toward the trailing edge -- are visible along the specimen's margins.

Regmaglypts range from shallow impressions to deep pits several millimeters across. These features result from localized vortices in the boundary layer flow, where turbulent air removed material at different rates across the surface. The depth and distribution of regmaglypts indicate the intensity and duration of atmospheric heating this specimen experienced before deceleration reduced ablation rates.

Scientific context

Ordinary chondrites formed 4.567 billion years ago in the protoplanetary disk, accreting from dust and millimeter-sized chondrules before their parent asteroids underwent thermal metamorphism. The H, L, and LL groups are distinguished by their iron content and oxidation state, reflecting formation at different heliocentric distances where temperature and oxygen fugacity varied. This specimen's classification remains pending laboratory analysis, but magnetic response provides preliminary constraint on likely group membership.

Oriented meteorites represent a small fraction of recovered falls and finds. Most meteorites tumble chaotically during atmospheric entry, producing uniform fusion crust without directional features. Stable orientation requires specific mass distribution and entry angle, making oriented specimens valuable for studying ablation physics and atmospheric flight dynamics. For more on meteorite classification and formation, see Learn About Meteorites.

Frequently asked questions

Is this meteorite authenticated? This specimen is an authenticated ordinary chondrite, confirmed through visual inspection, magnetic response testing, and comparison with classified reference material. While full laboratory classification (determining H, L, or LL group and petrologic type) has not been completed, the specimen exhibits all diagnostic features of an ordinary chondrite meteorite: chondritic interior texture, fusion crust, regmaglypts, and appropriate magnetic signature. A certificate of authenticity documenting these characteristics is included. For classified ordinary chondrites, see the Meteoritical Bulletin database at lpi.usra.edu/meteor/metbull.php.

What does flight-oriented mean? Flight orientation occurs when a meteorite maintains the same face forward throughout atmospheric entry, rather than tumbling randomly. This stable flight produces asymmetric features: pronounced regmaglypts and smooth crust on the leading face, with flow lines extending toward the trailing edge. Oriented specimens are less common than randomly oriented stones.

What is included with this specimen? This 635.58g individual, with a certificate of authenticity documenting its characteristics and find information. No display stand is included.

Why is this specimen unclassified? Classification requires laboratory analysis including thin section petrography, mineral chemistry determination, and sometimes oxygen isotope measurement. These procedures cost several hundred dollars and require destructive sampling. Many recovered meteorites, particularly ordinary chondrites from Northwest Africa, remain unclassified due to the cost-benefit ratio of full analysis. Unclassified status does not affect authenticity -- this is a confirmed meteorite.

What are contraction cracks? Contraction cracks form when fusion crust cools rapidly from ablation temperatures to ambient temperature within seconds of meteorite deceleration. The glassy crust shrinks faster than the interior, creating tensile stress that fractures the surface. These cracks are diagnostic features of genuine fusion crust and cannot be replicated artificially.

Display and collection value

At 635.58g, this specimen offers substantial visual presence while remaining affordable compared to classified ordinary chondrites with published Meteoritical Bulletin entries. The oriented geometry and exceptional crust preservation make this suitable for educational display, demonstrating atmospheric entry phenomena to students and public audiences. Collectors focused on fusion crust quality or oriented specimens will find the regmaglypt development and thermal cracking particularly well expressed on this piece.

The unclassified status provides an opportunity to acquire a large, visually striking ordinary chondrite at a lower price point than similarly sized classified stones. For collectors building Chondrites collections, this specimen documents atmospheric entry processes with clarity comparable to more expensive oriented falls. The fresh condition indicates recent recovery, with minimal terrestrial weathering degrading the original surface features.

Meteoritical Bulletin entry: This specimen has not been submitted for formal classification. | Find, Morocco, 2025