Description
Dual lithology. Really great full slice weighing 12.5g. Sold in a box with label/certificate.
Northeast Africa 053 (NEA 053)
(Northwest Africa)
Purchased: 2023
Classification: Martian meteorite (Shergottite)
History: Reportedly this stone was found in Libya.
Petrography: (K. Metzler, IfP) Igneous rock, dominated by elongated pyroxene grains (low-Ca and Ca-rich pyroxene) up to 3 mm and isometric olivine grains up to 2.5 mm, with an interstitial mixture of lathy skeletal plagioclase and pyroxene grains. Olivine and pyroxene crystals show igneous chemical zoning. Point counting on thin section images revealed 33 vol% olivine, 40 vol% pyroxene, and 27 vol% plagioclase. The latter has been completely transformed to maskelynite. Accessories are an SiO2 polymorph, ilmenite and titanomagnetite.
Geochemistry: Mineral compositions and geochemistry: Mean mineral compositions: Olivine Fa46.0±12.9 (Fa28.5-62.9); Fe/Mn (at.): 52.9; n=11. Low-Ca pyroxene Fs31.4±9.5 Wo7.2±2.8 (Fs25.4-47.6Wo4.7-12.6); Fe/Mn (at.): 29.9; n=12. Ca-rich pyroxene Fs23.0±1.4Wo30.5±3.7 (Fs21.5-25.9Wo26.0-37.2); Fe/Mn (at.): 32.4; n=14. Plagioclase (maskelynite) An46.3±2.3Or2.4±0.5 (An43.0-49.8Or1.7-3.1); n=12. Fusion crust composition (wt%): Na2O: 1.3; MgO: 14.5; Al2O3: 6.2; SiO2:48.1; P2O5: 0.8; K2O: 0.1; CaO: 7.4; TiO2: 0.8; Cr2O3: 0.4; MnO: 0.5; FeO: 19.7
Classification: Martian (Shergottite, olivine-bearing), based on texture and mineral chemistry.
