Northwest Africa 14419 (NWA 14419)

(Northwest Africa)

Purchased: 6 Apr 2021

Classification: Ordinary chondrite (H5)

History: CAlexander acquired the stone on April 6, 2021, from John A. Shea (IMCA 3295). Shea purchased the stone from Dean Bessey on April 12, 2016.

Physical characteristics: Physical Characteristics (M. Hutson, C. Alexander): The meteorite is roughly equant and faceted, with three larger faces and two smaller ones that approximate a fourth face; the sides are about 15 cm across. The exterior is a dark reddish brown with patches of darker weathered remnant fusion crust. The largest face shows well developed polygonal fractures on a weathered fusion surface. One of the two smaller faces shows well developed regmaglypts which are a light orange-brown in their centers. Cut surfaces show areas with fairly discrete chondrules, including a few rimmed chondrules; other areas have less obvious chondrules and bigger metal grains, suggesting the sample is a breccia. Extensive oxide veining is visible on cut surfaces.

Petrography: (M. Hutson, A. Ruzicka, Cascadia): Parts of the thin section show discrete chondrules set amidst a weathered and fractured coarse-grained matrix; other areas have indistinct chondrules the grade into the surrounding material. Boundaries between clasts are obscured by extensive fracturing and veining. Some chondrules appear to contain devitrified glass, while secondary recrystallized feldspar (up to 50 µm across) is present between chondrules.

Geochemistry: Low-Ca pyroxene grains were analyzed separately for areas with distinct chondrules versus areas with less distinct chondrules; the Fs and Wo contents for the two areas were identical. Olivine Fa_18.4±0.1, N=29; Low-Ca pyroxene Fs_16.4±0.2Wo_1.0±0.2, N=24; Plagioclase feldspar Ab_84.1±0.5Or_5.3±1.8, N=5.

Classification: H5 based on the combination of chemistry and texture. Olivine and pyroxene chemistry are consistent with an equilibrated H chondrite. The texture suggests a breccia containing fragments with a petrographic grade near the 4/5 boundary mixed with slightly higher petrographic grade 5 material.

Specimens: Cascadia holds 111.8 g in three pieces, as well as a polished thin section and material in a butt; CAlexander holds the main mass.