NORTHWEST AFRICA 999

Multiple stones and fragments totaling ~823 g were purchased in Morocco by an association of meteorite collectors known by the name of Trinity Meteorites. The exterior of this eucrite is covered with black fusion crust, and the interior is light tan in color with a very fine-grained texture consisting of mineral grains of pyroxene and plagioclase.

Northwest Africa 999 is a brecciated eucrite composed of very fine-grained basaltic material, which represents both the host and the clasts within the meteorite. The very fine-grained texture of this eucrite is consistent with rapid cooling from an extruded igneous melt. Moreover, it exhibits the typical thermal metamorphic features characteristic of other equilibrated eucrites. From a preliminary analysis performed by UCLA, NWA 999 was determined to be an extremely fine-grained eucrite that is slightly Fe-rich and REE-rich. Black mineral grains (chromite?) are interspersed throughout the matrix, and a rare FeNi-metal grain is present in the specimen shown above. This eucrite was low to moderately shocked and is cross-cut by thin, dark gray, shock-melt veins. The specimen of NWA 999 shown above is a 2.44 g slice.

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