Northwest Africa 10999
Classification: Ordinary chondrite (H5)
Physical characteristics: The surface of the stone is moderately weathered and dark red to brown. There is no fusion crust.
Petrography: (L. Pagé, UOtt) The stone is matrix poor (15 vol.%) and chondrule rich (75 vol.%), with an overall recrystallized texture. Some chondrules can be discerned, but many have poorly-defined edges. Chondrules range in size (0.1-1.0 mm), with an average of 0.4 mm. Chondrule types include BO, RP and POP. Mesostasis is recrystallized to plagioclase. Some metal and sulfides (~30%) are oxidized.
Geochemistry: (EPMA) Olivine Fa17.7±0.7 (n=27). Low-Ca pyroxene Fs15.3±0.6Wo1.6±2.1 (n=22). Plagioclase An16.4±14.2 (n=12). Cl-apatite (EDS, wt%): Ca=42.5, O=33.1, P=19.1, Cl=5.3. Kamacite (EDS, wt%): Fe=92.8, Ni=7.2. Troilite (EDS, wt%): Fe=64.3, S=35.7.