Northwest Africa 15682 (NWA 15682)

(Northwest Africa)

Purchased: 2022

Classification: HED achondrite (Howardite)

History: Eleven samples of varying sizes (main masses: 116, 131, 147, 204 g) were found in Northwest Africa. Adrián Contreras Gómez-(CRATER meteorites) purchased the meteorites from Hmad Ait Hssain, in Errachidia, Morocco on July 29, 2022.

Physical characteristics: Sample is a rounded stone completely coated with a glossy black fusion crust. Clasts are visible through the crust. The cut face shows the sample has a brecciated interior composed of white, gray and dark-colored clasts in a light-gray host.

Petrography: Description and classification (A. Love, App) Sample is a breccia composed of mineral grains and lithic clasts that share a weak orientation. Mineral fragments are: low and high Ca pyroxenes (some are exsolved), rare olivine and plagioclase. Lithic fragments are: rare porphyritic and cumulate clasts, equilibrated clasts, shock melted-breccias, glassy fragments and ~8 vol% carbonaceous chondrite clasts (showing CAI’s and chondrules). Additional minerals are: FeNi grains, troilite, merrillite, ilmenite, chromite and secondary calcite.

Geochemistry: (A. Love, App) Olivine (Fa_19.7±10.1, Fe/Mn=40.8±3.8, n=3); low Ca-pyroxene (Fs_29.5±14.2Wo_2.1±1.0, Fe/Mn=28.3±1.9 n=21); pigeonite (Fs_48.5±6.5Wo_11.0±7.3, Fe/Mn=31.4±2.6, n=3); high Ca pyroxene (Fs_34.5±4.6Wo_33.7±7.1, Fe/Mn=31.3±2.2, n=3); plagioclase (An_93.9±1.5Or_0.1±0.2, n=6).

Classification: HED achondrite (howardite) Sample is composed of ~62 vol% diogenite and ~30 vol% eucrite. Textures and mineral compositions suggest the sample is a HED polymict breccia.

Specimens: Adrián Contreras Gómez (CRATER meteorites) holds the main mass. A polished thin section and an individual weighing 34.56 g are on deposit at App.