Sold in a membrane box with label/certificate of authenticity.
Northwest Africa 11086 (NWA 11086)
Find: 2016 May
Classification: Carbonaceous chondrite (CM, anomalous)
History: Reportedly found near Foum Zguid, Morocco.
Physical characteristics: Dark brown stones. Cut surface reveals a lighter brown interior with small chondrules.
Petrography: Well delineated chondrules set in a iron-rich fine grained matrix. Matrix 58 vol%, chondrules and chondrule fragments 42 vol% (from point counting, N=293). Average apparent chondrule diameter 240±120 μm (N=38). Rare metal as ~1 μm spherical inclusions in silicates. X-ray diffraction does not reveal the presence of phyllosilicates.
Geochemistry: Olivine Fa0.9-32.7, average Fa14.2±12.2, PMD 81%, FeO/MnO = 79 (N=13), Cr2O3 on ferroan olivine 0.36±0.09 wt% (N=10). Orthopyroxene Fs1.4±0.1Wo1.1±0.1 (N=2). Oxygen isotopic composition (J. Gattacceca, C. Sonzogni, CEREGE) from analysis of one acid-washed 1.5 mg aliquot of a powdered homogenized 475 mg bulk sample is δ17O=-0.40‰, δ18O=6.17‰ , Δ17O=-3.63‰ (linearized, slope 0.5247, analytical uncertainties 0.08‰, 0.12‰, 0.03‰ respectively). Magnetic susceptibility log χ (× 10-9 m3/kg) = 3.41.
Classification: Carbonaceous chondrite (CM-an). Severe weathering.
Mass (g): 373
Weathering grade: Severe
Fayalite (mol%): 14.2±12.2 (N=13)
Ferrosilite (mol%): 1.4±0.1 (N=2)
Wollastonite (mol%): 1.1±0.1
Magnetic suscept.: 3.41
Classifier: J. Gattacceca, B. Devouard, CEREGE
Type spec mass (g): 22.64
Type spec location: CEREGE
Main mass: Fabien Kuntz and Pierre-Marie Pelé
Comments: work name K313; submitted by Jérôme Gattacceca