NWA 17691 (14.26 gram)

Classification: Diogenite-melt breccia W-low / S-moderate
Place/Time: 2024 in Algeria
Mass: 2000g

History: The meteorite was purchased from a dealer in Algeria.
Physical characteristics: Grayish rock with some fusion crust.
Petrography: (A. Greshake, L. Eisgruber, MNB) Achondritic melt breccia composed of up to 7 mm sized low Ca-pyroxene and up to 5 mm sized feldspar crystals set in a fine-grained cataclastic matrix of related material containing abundant fineley recrystallized black shock melt regions. Mineral fragments in contact with the shock melt frequently show resorption textures. Major silicate phases are low-Ca pyroxene often containing lamellar and blebby Ca-pyroxene exsolutions plus Ca-rich plagioclase (about 20 vol%). Minor phases include chromite, troilite, and Ni-free metallic iron.
Geochemistry: low-Ca pyroxene: Fs_35.0±0.1Wo_1.9±0.1 (Fs_34.9-35.1Wo_1.8-2.0, FeO/MnO=27-30, n=7); Ca-pyroxene: Fs_13.6±0.5Wo_45.0±0.4 (Fs_13.1-14.3Wo_44.1-45.2, FeO/MnO=21-24, n=7); calcic plagioclase: An_91.3±1.3 (An_89.7-93.4, n=7)
Classification: Diogenite-melt breccia, noritic