Northwest Africa 10455 (NWA 10455)

(Northwest Africa)

Purchased: Feb 2004

Classification: Ordinary chondrite (L6)

History: Obtained by Edwin Thompson from a Moroccan Trader in Tucson, Arizona, at the February 2004 Tucson Gem and Mineral Show. Samples acquired by Cascadia in February 2004 and October 2015.

Physical characteristics: Exterior is partly black and shiny, and partly reddish. The cut face displays an obvious breccia texture with light brown stained clasts (up to 1 cm across) separated by dark veins of various thickness.

Petrography: Clasts with granoblastic texture and highly indistinct chondrule boundaries are enclosed in numerous dark melt veins up to 1 mm thick, which occupy up to ~30% of the rock. Maskelynite occurs close to veins. Feldspathic phases often >50 μm across. Metal grains are heavily weathered, but troilite is mostly unweathered. About 4% metal overall (remaining).

Geochemistry: (K. Farley and A. Ruzicka, Cascadia) Olivine (Fa_26.0±0.4, Fe/Mn = 48.9±4.5 at., N = 20), low-Ca pyroxene (Fs_21.7±0.4Wo_1.6±0.2En_76.7±0.4, Fe/Mn = 28.3±2.0 at., N = 13), feldspar (Ab_74.2±6.7An_16.0±3.4Or_9.9±3.5, N = 7).

Classification: Veined L6 chondrite based on textures, mineral chemistry, and metal volume.

Specimens: Cascadia holds the entire sample, including 103.4 g in two pieces as well as two polished thin sections and two potted butts.