A stone meteorite weighing 605 g was purchased by M. Graul and a sample sent for analysis and classification to the Institut für Planetologie in Münster, Germany (K. Metzler). Northwest Africa 13400 was classified as an C3-ungrouped chondrite.
This carbonaceous chondrite has a low matrix abundance of 17 vol% with metal-bearing chondrules (up to 2.8 mm; ave. 0.48 mm), chondrule fragments, and CAIs (up to 3.8 mm). An O-isotopic analysis was conducted at the Open University (R. Greenwood), and the meteorite has an oxygen three-isotope plot within the CVCK field. After further in-depth analyses of NWA 13400 as well as Coolidge (C4), Loongana 001 (C4), Los Vientos 051 (C3.9), and NWA 033 (C3.9), Metzler et al. (2021) assigned these five meteorites to a new CL group which derives its name from Loongana 001. References have been made by some investigators to other potential members of the CL group, including HaH 073 and Sahara 00182, and perhaps NWA 779 and Sah 00177 (see the Coolidge page for further information about this group).
Northwest Africa 13400 is shocked to stage S2 and is weathered to a grade of W2/3. The specimen of NWA 13400 shown above is a 0.847 g partial slice. The photos below show the reverse side and an edge-on view of this specimen, courtesy of Mirko Graul.