NWA 18048 Eucrite-pmict Meteorite Slice, 120.00g, Mirror Polished HED Achondrite from Vesta

Mirror-polished polymict eucrite with vivid clast structure

This 120.00g slice showcases the complex architecture of a polymict eucrite breccia. The mirror polish on one face reveals distinct light and dark clasts suspended in an impact-processed matrix. Lighter eucritic fragments contrast sharply against darker melt zones, creating a mosaic that documents Vesta's violent surface history. The finish brings out fine-scale details invisible in rough specimens: clast boundaries, melt veins threading between fragments, and variations in mineral grain size across different lithologies.

At 120.00g, this specimen offers substantial display presence. The slice is large enough to show the full spectrum of polymict textures while remaining manageable for cabinet storage. The mirror polish eliminates surface irregularities that can obscure internal features, making this piece suitable for detailed examination under magnification or display lighting.

Brecciation and impact melt architecture

The slice preserves multiple generations of impact processing. Eucritic clasts—fragments of basaltic crust from Vesta's surface—appear as angular to subangular inclusions. These clasts vary in size and composition, indicating they were excavated from different depths or locations on the asteroid before being mixed together. The matrix surrounding these fragments contains impact melt, dark material formed when kinetic energy from high-velocity collisions liquefied rock.

Melt veins cut through the specimen in irregular pathways. These veins represent shock-melted material that intruded into fractures during impact events. The thickness and distribution of these veins indicate the intensity of the collisions that created this breccia. Some clasts show sharp, well-defined boundaries against the matrix, while others grade into surrounding material, suggesting partial melting or recrystallization at their margins.

Vesta's basaltic crust and HED meteorite formation

NWA 18048 originated from asteroid 4 Vesta, the second-largest body in the asteroid belt. NASA's Dawn spacecraft confirmed that eucrites, diogenites, and howardites—collectively called HED meteorites—come from Vesta's differentiated crust and mantle. Eucrites specifically represent basaltic material from Vesta's surface, formed when the asteroid's interior melted early in solar system history. Magma rose to the surface and crystallized into basaltic crust, similar to lunar mare basalts or terrestrial flood basalts.

Polymict eucrites like this specimen formed when massive impacts shattered Vesta's crust, mixing fragments from different crustal layers. The mixing process created breccias containing both pristine eucritic material and impact-modified components. Study of these meteorites has revealed Vesta's thermal history, differentiation processes, and the role of impact bombardment in shaping asteroid surfaces. For more context on meteorite classification and identification, see Learn About Meteorites.

Frequently asked questions

Is this meteorite authenticated? Yes. NWA 18048 is classified in the Meteoritical Bulletin as a eucrite-pmict. You can verify the classification here: Meteoritical Bulletin entry for NWA 18048. This specimen includes a certificate of authenticity documenting its classification, weight, and origin.

What does "pmict" mean in the classification? The abbreviation "pmict" stands for polymict, indicating this eucrite is a breccia containing multiple rock types. Unlike monomict eucrites (single-composition rocks), polymict eucrites contain clasts of different compositions mixed together during impact events. This specimen contains eucritic basalt fragments, impact melt, and possibly minor amounts of other HED material, all welded together by subsequent impacts.

Why is this specimen mirror polished? Mirror polishing removes surface irregularities and reveals internal structure with maximum clarity. The technique uses progressively finer abrasives to create an optically smooth surface that reflects light uniformly. This finish allows detailed examination of clast boundaries, melt veins, and mineral textures that would be obscured on a rough or sawn surface. It also makes the specimen suitable for photomicrography and educational display.

What is included with this specimen? You receive the 120.00g mirror-polished slice and a certificate of authenticity. The certificate documents the meteorite's classification, weight, and find location. No display stand is included.

How did this meteorite reach Earth from Vesta? Large impacts on Vesta ejected fragments into space at velocities exceeding the asteroid's escape velocity (approximately 360 meters per second). These fragments entered independent orbits around the Sun, where gravitational interactions with planets gradually altered their trajectories. Eventually, some fragments intersected Earth's orbit and fell as meteorites. The process can take millions of years from initial ejection to atmospheric entry.

Display-grade HED specimen for planetary collections

Collectors focused on differentiated asteroids prioritize polymict eucrites for their scientific and visual complexity. This 120.00g slice combines size, structural clarity, and professional preparation. The mirror polish eliminates the preparation artifacts common in hastily finished specimens—saw marks, uneven surfaces, edge chipping—that detract from serious collections.

Large eucrite slices are underrepresented in the market compared to chondrites or common iron meteorites. Most NWA finds are recovered as small fragments requiring reassembly or irregular pieces unsuitable for full polishing. A complete slice at this weight, showing clear polymict textures across its entire face, represents a specimen tier above typical dealer offerings. For collectors building comprehensive HED suites, explore our complete Eucrites and HED Meteorites collections.

Meteoritical Bulletin entry: NWA 18048 | Classification: Eucrite-pmict | Find, Northwest Africa, 2024