Northwest Africa 13426 (NWA 13426)
(Northwest Africa)
Purchased: 2020
Classification: Lunar meteorite
History: Many stones totaling 137.3 g were found and subsequently purchased from a meteorite prospector in Tindouf, Algeria, in March, 2020.
Physical characteristics: Samples are coated with a layer of light-orange caliche, and have a dark-colored interior containing clastic crystalline debris.
Petrography: Description and classification (A. Love, App): Sample is a breccia composed of rounded to angular 25.1-2241 μm (avg. length 272 μm, n=145) mineral grains and lithic clasts with poikilitic, basaltic and brecciated textures set within a melt matrix. Sample contains clear glassy spheres, fragments and glassy schlieren textured objects. Additional minerals are FeNi grains, a silica polymorph, chromite, ilmenite, titanomagnetite and troilite.
Geochemistry: (A. Love, App) Olivine Fa30.1±10.0 (Fa19.7-40.5, Fe/Mn=80.3±6.2, n=8); low-Ca pyroxene Fs21.2±2.5Wo3.2±0.2 (Fs19.5-23.0Wo3.1-3.4, Fe/Mn=48.8±1.3, n=2); pigeonite Fs32.4±4.9Wo11.6±3.9 (Fs23.0-37.7Wo5.9-18.0, Fe/Mn=51.9±2.8, n=5); high-Ca pyroxene Fs29.1±7.7Wo29.7±4.0 (Fs21.4-38.4Wo21.8-32.1, Fe/Mn=54.0±5.9, n=6); plagioclase An96.4±0.9Or0.2±0.2 (n=7).
Classification: Lunar (feldspathic breccia). Based on textures, melt matrix component and mineral compositions, this sample is a feldspathic breccia.
Specimens: Kuntz holds the main masses. A polished thin section and 10 fragments weighing 21.53 g are on deposit at App.