Writeup from MB 112: Northwest Africa 15788 (NWA 15788) (Northwest Africa) Purchased: 2022 Nov Classification: HED achondrite (Diogenite, polymict) History: Many similar-appearing stones (total weight 3912 g) were found together near Kidal, Mali in November and December 2022 and purchased by Mbark Arjdal in November 2022 and February 2023. Petrography: (A. Irving, UWS, and P. Carpenter, WUSL) Breccia composed predominantly crystalline debris derived from diogenites (zoned low-Ca pyroxene, anorthite and Ti-free chromite) with vol.% of eucritic material (as grains of exsolved pigeonite, labradorite, ilmenite and symplectitic intergrowths composed of silica polymorph+fayalite+hedenbergite). Minor kamacite and secondary Fe oxide are also present. Geochemistry: Orthopyroxene cores (Fs23.2-26.5Wo1.8, FeO/MnO = 31-34, N = 2), pigeonite rims (Fs33.6-34.8Wo8.2-6.8, FeO/MnO = 28-30, N = 2), ferroan pigeonite rim (Fs53.3Wo15.7, FeO/MnO = 35), subcalcic augite (Fs44.0Wo25.5, FeO/MnO = 31), low-Ca pyroxene hosts (Fs55.3-63.4Wo3.9-5.2; Fs39.0Wo5.1; FeO/MnO = 30-34, N = 3), augite exsolution lamellae (Fs28.8-28.9Wo40.5-41.6; Fs19.3Wo41.3; FeO/MnO = 29-33, N = 3), hedenbergite (Fs58.7Wo33.1, FeO/MnO = 42), fayalite (Fs82.7, FeO/MnO = 43), labradorite (An65.0-69.9Or1.4-1.7, N = 2), anorthite (An93.6-94.6Or0.2, N = 2). Classification: Diogenite (polymict breccia). I am a member of the Meteoritical Society (#7743) and have been collecting meteorites for more than 15 years.