Northwest Africa 13518. Purchased: 2020 Mar Classification: Rumuruti chondrite (R4-5) History: Purportedly found in 2019 at the border between Algeria and Mali. Purchased by Mohamed Ali (972 g) and Miguel Angel Contreras (1662 g) from a Saharaui dealer in Mauritania in March 2020. Physical characteristics: Many pieces between a few grams and >500 g, some with fusion crust. Petrography: (K. Metzler, IfP) Chondritic genomict breccia, consisting of dark host material and light chondritic clasts up to ~2 cm. The host material is of petrologic type 4. It consists of chondrules and chondrule fragments, embedded in recrystallized interchondrule material. Relictic Mg-rich olivine cores can be occasionally observed. The light clasts are strongly metamorphosed and represent type 5 material with clearly recognizable chondrules. Geochemistry: Mineral compositions and geochemistry: Dark host material : Mean olivine composition: Fa38.7±0.2 (Fa38.4-39.0); n=10; mean low-Ca pyroxene composition Fs19.8±6.7Wo1.0±1.0 (Fs7.6-29.9Wo0.2-2.9); n=8. Light clast of petrologic type 5: mean olivine composition Fa38.8±0.3 (Fa38.1-39.2); n=8; mean low-Ca pyroxene composition: Fs29.9±0.4Wo1.3±0.5 (Fs29.1-30.6Wo0.6-2.2); n=10. Accessories in both lithologies are troilite and pentlandite; no metal was found. Classification: R chondrite based on mineral chemistry. Genomict breccia, consisting of clasts of petrologic type 5 (equilibrated olivine and pyroxene), embedded in host material of petrologic type 4 (equilibrated olivine and unequilibrated pyroxene). Shock stage: C-S3 Weathering grade: Low Classifier: K. Metzler, IfP. This lot comes with certificate of authenticity. Thanks for your interest.