A collection of 32 stones devoid of fusion crust, weighing together 7,020 g, was found in Northwest Africa. The lot was subsequently sold to G. Hupé in Laâyoune, Morocco, and a sample was sent for analysis and classification to the University of Washington in Seattle (Irving and Kuehner). Northwest Africa 4473 was determined to be polymict brecciated diogenite. The 1,023 g meteorite designated NWA 4965 was determined to be paired.
Petrographic analyses of this diogenite revealed a composition predominantly of orthopyroxene that documents the mixing of at least three compositional components. Lesser amounts of olivine, augite, chromite, and silica are present, along with rare Ca-plagioclase, FeS and kamacite. Petrographic observations have not detected a eucritic component. Northwest Africa 4473 exhibits ubiquitous light greenish-yellow angular clasts embedded in a matrix containing a variety of precursor lithologies.
Additional details about the polymict diogenite group can be found on the NWA 1239 page. To see an alternative classification system for the diogenites and dunites based on mineralogical and petrographical features, proposed by Beck and McSween (2010) and modified by Wittke et al. (2011), click here. The photo of NWA 4473 shown above is a 4.0 g partial slice that was expertly prepared by Greg Hupé.