NWA 11704, Polymict Eucrite Breccia, Polished Endcut, 6.1g

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NWA 11704 meteorites were first recovered out of the Saharan Desert of Mauritania in early 2018. The find consisted of many small fragments that weighed a combined 1.1kg of material. Specimens were analyzed by Dr. Tony Irving at UWS and classified as a polymict eucrite breccia from the HED class of Vestan meteorites. This is a meteorite that straddles the line between diogenite and eucrite. It is a predominately eucritic groundmass with diogenitic clasts jumbled in to the breccia. It has a greenish color to it with contrasting whitish clasts and amber-colored inclusions.

The specimen being offered here has been professionally cut and polished. It is an endcut that weighs approx. 6.1 grams. The uncut end has a natural patina of wind-polished desert varnish and remnant fusion crust. The cut face has a glossy, mirror-like polish that ideal for examination under magnification. This endcut shows the interior clasts very well.

Refer to the photos. The black centimeter cube is shown for scale and is not included. You are purchasing the specimen shown. Your purchase will include an ID label.

From the Meteoritical Bulletin entry on NWA 11704 :

Northwest Africa 11704 (NWA 11704)


Purchased: 2018 Jan

Classification: HED achondrite (Eucrite, polymict)

History: A batch of about 50 stones with similar appearance found together in Mauritania was purchased by John Higgins in January 2018 from a Mauritanian dealer.

Petrography: (A. Irving and S. Kuehner, UWS) Breccia consisting predominantly of gabbroic eucrite clasts, some ophitic eucrite clasts and sparse clasts of feldspathic diogenite in a finer grained matrix. Minerals include exsolved pigeonite, calcic plagioclase (exhibiting undulose to polycrystalline microstructure), silica polymorph, ilmenite, Ti-chromite, Ti-poor chromite, troilite and minor barite. Feldspathic diogenite clasts consist mainly of relatively ferroan orthopyroxene with subordinate anorthite and minor clinopyroxene.

Geochemistry: Orthopyroxene host (Fs58.5Wo4.6, FeO/MnO = 35), clinopyroxene exsolution lamella (Fs28.1Wo41.0, FeO/MnO = 34), orthopyroxene host (Fs44.5Wo2.2, FeO/MnO = 30), clinopyroxene exsolution lamella (Fs17.8Wo43.8, FeO/MnO = 25), plagioclase (An86.6Or0.8). Minerals in feldspathic diogenite clast: orthopyroxene (Fs33.2-33.8Wo1.7-2.4, FeO/MnO = 29-32, N = 2), clinopyroxene (Fs10.8Wo45.8, FeO/MnO = 21), anorthite (An95.4Or0.2).

Classification: Eucrite (polymict breccia).