Groundmass microcrystalline oxides from the Marsfontein pipe (Republic of South Africa), Catoca, Camachia and others Angolan kimberlite pipes - Garanin, V.K.; Anashkin, S.M.; Bovkun, A.V.; Jelsma, H.; Shmakov, I.I.; Garanin, K.V. (International Kimberlite Conference: Extended Abstracts, 2012)