Djebel Chaab 004 (Cha 004) 25.33805°N, 1.14363°E Adrar, Algeria Find: 2022 Dec 27 Classification: HED achondrite (Diogenite, anomalous) History: Reportedly, a group of meteorite hunters found several pieces of this material on December 27, 2022 in the Djebel Chaab DCA, Algeria. Petrography (K. Metzler, IfP): Polymict achondritic breccia, consisting of mineral fragments and few lithic clasts (diogenitic and eucritic), embedded in fine-grained related debris. The material is shock-compacted and thin shock veins are present. Diogenite component >90 vol%. This breccia is dominated by fragments of olivine and low-Ca pyroxene with unusually large ranges of chemical compositions. The eucrite component occurs in the shape of mineral fragments (exsolved pyroxene, plagioclase, SiO2 polymorph) and as small lithic clast. Accessories are Cr-spinel and Ni-bearing metal (3-4 wt% Ni). Geochemistry: Mineral compositions and geochemistry: Diogenitic clasts: Mean olivine composition: Fa15.9±5.8 (Fa8.7-28.4); Fe/Mn (at.): 44.8; n=18. Mean pyroxene composition: Fs23.5±5.9Wo2.3±1.1 (Fs11.9-31.2Wo0.4-3.9); Fe/Mn (at.): 28; n=15. Eucrite clasts: Mean composition of low-Ca pyroxene (host): Fs63.3±0.3Wo2.4±0.4 (Fs62.8-63.7Wo1.9-2.8); Fe/Mn (at.): 33; n=5. Mean composition of Ca-rich pyroxene (exsolution lamellae): Fs25.7±4.5Wo40.7±1.8 (Fs21.2-31.5Wo36.6-42.2); Fe/Mn (at.): 33; n=11. Mean plagioclase composition: An89.6±5.1Or0.4±0.5 (An78.3-95.1Or0.0-1.5); n=15. Classification: Diogenite (polymict, anomalous). The diogenite component is characterized by unusually large chemical variations of both olivine and pyroxene, which distinguishes this rock from other polymict diogenites. Shock stage: high Weathering grade: low Classifier: K. Metzler, IfP This lot comes with certificate of authenticity. Thanks for your interest.