Adrar 013 Lunar Meteorite Slice, Melt Breccia, 2.67g, Complete Section

Complete cross-section preserving impact melt structure

This 2.67g slice captures the full width of Adrar 013, presenting an uninterrupted view from edge to edge through the specimen's impact-generated matrix. The cross-section format reveals how the once-molten material cooled and solidified, preserving angular clasts of anorthositic norite and gabbro suspended within the fine-grained melt matrix. Edge-to-edge continuity allows observation of textural variations across the entire specimen without interruption.

The slice's uniform thickness maintains consistent light transmission properties across its surface, making the contrast between darker mafic fragments and lighter anorthositic components readily visible. This geometric completeness distinguishes the piece from partial sections or end cuts, offering a representative sample of the internal structure throughout the meteorite's original mass.

Anorthositic clasts in impact melt matrix

The specimen displays the characteristic two-phase texture of lunar melt breccias: a fine-grained matrix formed from completely liquefied material surrounding angular fragments that remained partially solid during the impact event. The anorthositic components appear as lighter-toned regions, reflecting the plagioclase-rich composition of the Moon's ancient highland crust. Darker clasts represent the norite and gabbro components, indicating excavation from deeper crustal layers where pyroxene concentrations increase.

Clast boundaries remain sharp and well-defined, showing minimal reaction between fragments and matrix during cooling. This preservation indicates rapid solidification following the impact that generated the melt, consistent with ejection into the lunar vacuum where radiative cooling proceeds efficiently. The distribution of clast sizes and orientations records the turbulent mixing that occurred while the material remained molten.

Scientific context

Adrar 013 originated in the Moon's highland regions, where anorthositic rocks formed during the cooling of a primordial magma ocean approximately 4.4 billion years ago. The presence of norite and gabbro alongside anorthosite indicates the impact that created this melt breccia excavated through multiple stratigraphic layers, mixing ancient crustal material with younger intrusive rocks. This compositional mixing provides evidence for the Moon's differentiated internal structure.

Lunar meteorites reach Earth only after impact events deliver sufficient energy to accelerate fragments beyond the Moon's escape velocity of 2.4 km/s. The specimen's recovery in Algeria in 2023 adds to the limited sample of lunar material available outside government collections. Understanding lunar geology through meteorites complements spacecraft sample returns and provides context for planetary formation processes throughout the inner solar system.

Frequently asked questions

Is this meteorite authenticated? Yes. The Meteoritical Society classified Adrar 013 as a lunar melt breccia with anorthositic norite/gabbro composition. You can verify this classification in the Meteoritical Bulletin database. The specimen includes a certificate of authenticity documenting its classification and provenance.

What is a melt breccia? A melt breccia forms when hypervelocity impacts generate sufficient heat to partially or completely melt target rocks, which then cool rapidly while mixed with solid fragments. The resulting rock contains both crystallized melt matrix and angular clasts of material that remained solid during the impact event.

What does the anorthositic composition indicate? Anorthosite dominates the Moon's ancient highland crust, forming the bright regions visible from Earth. The anorthositic composition in this specimen confirms its origin from highland terrain rather than the darker, basalt-rich maria that cover portions of the lunar surface.

What is included with this specimen? The 2.67g slice ships with a certificate of authenticity. No display stand is included.

How did this material travel from the Moon to Earth? A meteoroid impact on the lunar surface ejected fragments at velocities exceeding 2.4 km/s, allowing them to escape the Moon's gravitational field. These fragments orbited the Sun until gravitational interactions with Earth captured them, resulting in their atmospheric entry and recovery in Algeria.

Collector significance

Lunar meteorites represent the only Moon rocks legally available to private collectors, as Apollo samples and robotic return missions remain in government custody. The 2.67g mass provides substantial material for study while remaining accessible to collectors building representative planetary specimen sets. The complete slice format maximizes observable surface area relative to weight, allowing detailed examination of the impact melt texture and clast distribution.

Adrar 013's recent classification in 2023 places it among the newest additions to the lunar meteorite inventory. The anorthositic composition links the specimen directly to the Moon's primordial crust, offering a tangible connection to the earliest stages of lunar differentiation. Collectors seeking scientifically significant material from the Moon's surface will find this specimen represents both the highland crust and the impact processes that have shaped lunar geology for billions of years. Browse additional specimens from Earth's celestial neighbor in the Lunar Meteorites collection.

Meteoritical Bulletin entry: Adrar 013 | Classification: Lunar melt breccia (anorthositic norite/gabbro) | Find, Algeria, 2023