NWA 10558 Mars Meteorite, Diabasic Shergottite
Tkw 14.3 g, find 2015
Classified by Dr. Anthony Irving, Washington University
Petrography: (A. Irving and S. Kuehner, UWS) Diabasic texture with some preferred orientation of inequidimensional pyroxene and maskelynite grains. Composed of prismatic grains of zoned clinopyroxene (up to 4 × 0.6 mm in size) plus subordinate, smaller laths of maskelynite together with accessory ilmenite, ulvöspinel, merrillite (some with chlorapatite rims) and pyrrhotite. Rare inclusions of silica polymorph are present in pyroxene.
Geochemistry: Low-Ca pyroxene (Fs 30.9-41.6Wo11.5-8.8, FeO/MnO = 28-35, N = 4), high-Ca pyroxene (Fs22.2-36.4Wo33.8-35.7, FeO/MnO = 28-32, N = 4), maskelynite (An52.1-52.4Or1.3-1.2, N = 2). The compositional ranges for pyroxene are more limited than in most other shergottites. Hf and Nd isotopes (M. Righter and T. Lapen, UHou): analysis of clean whole rock cutting dust gave ε176Hf = -19.49 and ε143Nd = -9.04, indicating that this specimen has affinities to enriched shergottites (like Shergotty).
Classification: Martian (diabasic shergottite, enriched).
Very nice and fresh. Carefully prepared pieces at only $ 290/ g !