Part slice – 1.28g.
Sold with label/certificate of authenticity.
Northwest Africa 11490 (NWA 11490)
Purchased: 2017 Apr
Classification: HED achondrite (Howardite)
History: Purchased by Fabien Kuntz in April 2017 from a dealer in Erfoud, Morocco.
Petrography: (A. Irving and S. Kuehner, UWS) Breccia composed of ~60 vol.% diogenitic orthopyroxene (as angular grains exhibiting undulose extinction), ~35 vol.% eucritic material and ~5 vol.% dark carbonaceous chondrite clasts. Most eucritic material consists of disaggregated grains of exsolved pigeonite, unexsolved pigeonite, subcalcic augite and calcic plagioclase, but some lithic clasts with subophitic and microgabbroic textures are also present. Accessory minerals include silica polymorph, chromite, ilmenite, fayalite, baddeleyite, troilite, pentlandite and Ni-poor metal.
Geochemistry: Diogenitic orthopyroxene (Fs27.6-29.7Wo3.6-3.8, FeO/MnO = 32, N = 2), orthopyroxene host (Fs64.0Wo1.9, FeO/MnO = 31), orthopyroxene host (Fs42.3Wo1.9, FeO/MnO = 35), clinopyroxene exsolution lamella (Fs15.4Wo45.4, FeO/MnO = 30), pigeonite (Fs45.9Wo9.1; Fs52.5Wo11.7; Fs55.9Wo23.3; FeO/MnO = 30-35; N = 3), subcalcic augite (Fs34.4Wo32.2, FeO/MnO = 28), fayalite (Fa85.4, FeO/MnO = 40), plagioclase (An91.1-92.8Or0.4-0.3, N = 2), forsterite in carbonaceous chondrite clast (Fa0.9), enstatite in carbonaceous chondrite clast (Fs0.6Wo0.9).
Specimens: 20.29 g including one polished thin section at PSF; remainder with Kuntz.