Viksdalen

Norway

Found 1992 July 4

Achondrite (eucrite)

Fragments of a single 470 g stone were found by Steffan Hatlestad, a 12-year-old boy, while walking in the mountains.  Mineralogy and classification (G. Raade, UOslo): the meteorite is a breccia with relic primary gabbroic textures. The main minerals are plagioclase (with undulatory extinction) and pyroxene (low-Ca pigeonite). They occur as angular clasts (0.05 to 0.7 mm) in a fine-grained groundmass; subrounded pyroxene grains may be up to 1.2 mm. Rounded clasts 2–3 mm in size show coarse ophitic to subophitic (gabbroic) textures. Accessory minerals are silica, ilmenite, titanian chromite, and troilite. Isolated plagioclase clasts and plagioclase laths from the larger, gabbroic clasts have similar composition, An₈₆ (mean of three analyses). Low Ca-pyroxene has a composition of Fs₅₉Wo₂. Exsolved augite lamellae vary in composition from Fs₂₆Wo₄₄ to Fs₃₁Wo₃₆. Scanning an exsolved pyroxene grain gave a bulk composition of Fs₄₄Wo₂₁. The host pyroxene has small inclusions of troilite, ilmenite, or plagioclase. Weathering grade:  W0. Chemical composition (G. Raade, UOslo): SiO₂ = 49.03%, Al₂O₃ = 11.58%, Fe₂O₃ = 0.82%, FeO = 17.85%, MnO = 0.53%, MgO = 7.12%, CaO = 9.85%, Na₂O = 0.58%, K₂O = 0.05%, TiO₂ = 0.92%, P₂O₅ = 0.07%. Specimens: main mass and type specimen, 459 g plus thin section, UOslo.