NWA 17920 Carbonaceous Chondrite Meteorite Slice, CK6, 28.53g, Complete Cross-Section with Fusion Crust

Complete cross-section through thermally processed carbonaceous material

This 28.53g slice captures the full profile of NWA 17920, a CK6 carbonaceous chondrite recovered from Mali in 2025. The polished surface exposes the specimen's entire interior structure from fusion crust to fusion crust, revealing how thermal metamorphism has recrystallized the original chondritic texture into a compact, homogenized matrix. Dark fusion crust borders frame the polished interior, documenting the atmospheric entry that delivered this material to Earth's surface.

CK6 represents the highest metamorphic grade within the Karoonda group of carbonaceous chondrites. At this petrologic type, sustained heating on the parent body has largely obliterated discrete chondrule boundaries, producing a fine-grained, equilibrated texture that contrasts sharply with the primitive structures preserved in lower-grade carbonaceous types. The oxidized mineralogy remains intact despite this thermal processing, maintaining the chemical signature that defines the CK classification.

The complete cross-section format makes this slice particularly effective for display, showing both the modified interior structure and the preserved exterior surface that survived atmospheric passage.

Structure and features

The polished face shows the characteristic fine-grained texture of type 6 metamorphism. Original chondrules have been largely erased through recrystallization, leaving a relatively uniform matrix punctuated by scattered mineral grains and occasional relict structures. The thermal processing that produced this texture occurred on the parent body over millions of years, driven by internal heat sources or impact events.

Fusion crust edges exhibit the glassy, blackened surface formed during the brief but intense heating of atmospheric entry. This exterior layer contrasts with the lighter interior tones visible on the polished face. The preservation of fusion crust around the slice perimeter confirms this specimen's orientation as a complete cross-section rather than an interior fragment.

The oxidized mineral assemblage typical of CK chondrites remains present despite metamorphic alteration. This oxidation state distinguishes CK material from reduced carbonaceous types and reflects formation conditions in a parent body region with available oxygen.

Scientific context

CK chondrites form a distinct subgroup within the carbonaceous chondrite classification, characterized by oxidized minerals and evidence of thermal metamorphism. The parent body for this group remains unidentified, though the oxidation state and metamorphic history suggest formation in a differentiated asteroid that experienced internal heating sufficient to recrystallize primitive materials without complete melting.

Type 6 classification indicates equilibration temperatures that homogenized mineral compositions and obliterated most original textural features. This thermal history provides insight into the interior conditions of small planetary bodies during the early solar system, when radiogenic heating and potential impact events drove thermal processing across a range of asteroid types.

The CK group's oxidized character sets it apart from more reduced carbonaceous types like CV or CO chondrites, demonstrating that carbonaceous material in the asteroid belt formed under varying oxidation conditions. For broader context on meteorite classification and formation, see Learn About Meteorites.

Frequently asked questions

Is this meteorite authenticated? Yes, NWA 17920 is officially classified in the Meteoritical Bulletin as a CK6 carbonaceous chondrite. You can verify this classification through the Meteoritical Bulletin database. This specimen includes a certificate of authenticity from Treasure Coast Meteorite Co. documenting its classification, weight, and provenance.

What does CK6 classification mean? CK indicates the Karoonda group of carbonaceous chondrites, characterized by oxidized minerals and thermal alteration. The number 6 represents the petrologic type, indicating the highest level of thermal metamorphism where original chondrules have been largely recrystallized into a homogenized texture. This reflects sustained heating on the parent body.

What is included with this specimen? This listing includes the 28.53g polished slice with preserved fusion crust edges and a certificate of authenticity. No display stand is included unless specifically noted in the product options.

How does CK material differ from other carbonaceous chondrites? CK chondrites are more oxidized and thermally processed than primitive carbonaceous types like CI or CM chondrites. While they retain the chemical signature of carbonaceous material, their metamorphic alteration and oxidation state reflect different formation or processing conditions compared to more pristine carbonaceous specimens.

What does a complete cross-section show that a partial slice does not? A complete cross-section preserves the full profile from exterior fusion crust through the interior structure to the opposite fusion crust edge, documenting both the atmospheric entry surface and the internal texture produced by parent body processes. This provides a more comprehensive view of the specimen's history than an interior-only fragment.

Collector significance

CK chondrites represent a minority classification within the carbonaceous chondrite group, making them less frequently available than ordinary chondrites or more common carbonaceous types. The combination of carbonaceous chemistry with high-grade metamorphic texture creates a specimen that bridges primitive and processed materials, appealing to collectors who focus on meteorite diversity and thermal history.

This 28.53g size provides substantial display presence while remaining accessible compared to larger fragments. The complete cross-section format with preserved fusion crust delivers both scientific content and visual appeal, showing the contrast between exterior and interior features in a single specimen. The recent classification in 2025 places this among the newest additions to the carbonaceous chondrite catalog.

For additional carbonaceous material with different preservation states and metamorphic grades, explore our Carbonaceous Chondrites collection. Collectors interested in other thermally processed stony material may also consider our Chondrites offerings.

Meteoritical Bulletin entry: NWA 17920 | Classification: Carbonaceous chondrite (CK6) | Find, Mali, 2025