Northwest Africa 13299 (NWA 13299)

Algeria

Purchased: 2020

Classification: Enstatite chondrite (EH3)

History: Fabien Kuntz purchased the 298.8 g sample from a nomad in Tindouf, Algeria, in 2020.

Physical characteristics: Sample has a brown weathered exterior, is irregular in shape, and has a distinctive odor of sulfur during cutting, grinding and polishing operations. The interior of the sample is metal-rich. Abundant small light-gray chondrules are visible on the cut face.

Petrography: Description and classification (A. Love, App): Sample shows a chondritic texture composed of ovoid chondrules and fragments with an average apparent diameter 299 µm (n=66) set within a fine-grained clastic matrix composed of opaques and silicates. Sample contains poikilitic chondrules with olivine chadacrysts and porphyritic chondrules contain clear isotropic mesostasis. Additional minerals are: daubréelite, niningerite, schreibersite, djerfisherite, rudashevskyite, troilite ( 2wt% Cr), perryite, Si polymorph, albitic plagioclase. Si-bearing kamacite has an average of 2.41 wt% Si.

Geochemistry: (A. Love, App) Low-Ca pyroxene, Fs_4.1±4.3Wo_0.6±0.5 (Fs_0.6-16.9Wo_0.2-2.4, n=18); olivine, Fa_0.6±0.2, Cr₂O₃=0.3±0.1 (Fa_0.4-0.9, n=7).

Classification: Enstatite chondrite (EH3, C-S3, W2). Textures, mineralogy, mineral chemistry, cathodoluminescence, chondrule diameters and magnetic susceptibility indicate this sample is an unequilibrated EH chondrite.

Specimens: Fabien Kuntz holds the main mass. A 31.27 g slice and polished thin section are on deposit at App.