CH Carbonaceous Chondrites

Northwest Africa 770 (20°20.80' N, 11°50.03' W)

Morocco
Found June 2000
Carbonaceous chondrite (CH)

NWA 770. Image source: http://www.meteorite.fr/en/forsale/CCH.htm#CH

An 18.1 g crusted stone was found north of Legaaida by a person prospecting for meteorites. Mineralogy and classification (T. Bunch and J. Wittke, NAU): similar to Allan Hills 85085 in texture, mineral modes (pyroxene/olivine = 3:1, Fe-Ni metal = 27 vol. %), and chondrule size (mean diameter = 23 μm), but with few "matrix lumps"; contains small, subrounded CAIs with pure gehlenite (MgO = 0.3 wt. %) and micron-sized perovskite; 80% of chondrules are cryptocrystalline, and consist of stoichiometric enstatite (FeO = 0.24 wt. %) and forsterite (FeO = 1.1 wt. %); rare refractory chondrules have Al-rich diopside cores with spinel inclusions and forsterite rims (FeO = 0.45 wt. %); metal grains average Ni = 6.1 wt. % and Cr = 0.47 wt. %; shock stage, S2; weathering grade, W1. Specimens: 3.2 g plus thin section, NAU; main mass with finder.