Name: Northwest Africa 4664 0.25g
This is an OFFICIAL meteorite name.
Abbreviation: NWA 4664
Observed fall: No
Year found: 2006
Mass: 20 kg
Northwest Africa 4664
Achondrite (diogenite, polymict breccia)
History and Physical characteristics: Many stones that weigh ~20 kg were purchased in Rissani, Morocco, in July 2006 by A. Aaronson and are part of a large strewn field in which at least 30 kg have been recovered.
Petrography: (T. Bunch and J. Wittke, NAU) A moderately shocked diogenite cataclastic breccia. Samples range from very matrix-rich to those that are matrix-poor and are composed of closely packed clasts. Mineral modes (vol%): orthopyroxene = 92, olivine = 4, plagioclase = 2, augite = 2, chromite and FeS = 1. Trace amounts of silica and metal are also present. The sample has at least two lithologies: one contains orthopyroxene with lowest FeO and without olivine; the other contains olivine with slightly more FeO-rich orthopyroxene. Orthopyroxene grains show minor amounts of shock lamellae and well-developed undulatory extinction. Plagioclase is partially isotropic.
Mineral compositions and Geochemistry: Orthopyroxene (Fs17.8-23Wo1.1-2.8; FeO/MnO = 30-37), olivine (Fa24.1-32.6; FeO/MnO = 52-56), plagioclase (An79), chromite (Cr/(Cr + Al) = 0.67).
Classification: Achondrite (diogenite, polymict breccia); moderate shock, minimal weathering. Most likely paired with NWA 4473.
Type sample: A 34 g sample is on deposit at NAU. Aaronson holds the main mass.
Submitted by: T. Bunch, NAU.
The internal matrix is quite interesting. This meteorite would make a fine addition to any collection. This material is very solid, takes an excellent polish and displays nicely.