Description: NWA 13791 is a striking example of an ungrouped achondrite meteorite, classified as exceedingly rare among meteorites. This unique slice weighs an impressive 19.851 grams and is distinguished by a perfect polish on one side, revealing the meteorite's intrinsic beauty characterized by rare vesicles and distinctive sulfide beads. Petrographic Overview The meteorite is composed primarily of an equigranular igneous rock matrix with the following features: - **Composition**: Approximately 85% of the meteorite consists of mafic components predominantly composed of olivine and low-calcium pyroxene, exhibiting calcium-rich pyroxene rims. The remaining 15% comprises fine-grained interstitial material, revealing the meteorite's complex formation process. - **Grain Size**: The average grain size varies between 300 to 1000 m, showcasing a well-structured arrangement that is characteristic of similar igneous materials. - **Oxidation**: Notably, metal and sulfide beads found within the specimen, measuring up to 800 m, have been completely oxidized due to terrestrial weathering, providing insight into the weathering processes these celestial bodies undergo. Classification Insights NWA 13791 stands out due to its classification as an ungrouped achondrite, which highlights its unique mineral composition that does not align with any known achondrite groups. However, it does exhibit some affinities to H and L ordinary chondrites, suggesting a complex genesis that warrants further study. Display and Certification This exquisite meteorite slice is not only a scientific phenomenon but also a remarkable collectible. It is presented with a Certificate of Authenticity (COA) card, ensuring its legitimacy and origin. Furthermore, it comes enclosed in a display case, making it a perfect addition for collectors, museums, or educational institutions looking to showcase a rare specimen of extraterrestrial origin. NWA 13791 is a testament to the beauty and mystery of the cosmos, providing a tangible connection to our universe and a remarkable opportunity for analysis and appreciation. Northwest Africa 13791 (NWA 13791) (Northwest Africa) Purchased: 2020 Classification: Ungrouped achondrite Geochemistry: Mineral compositions and geochemistry: Olivine grains show igneous chemical zoning, with increasing Fe concentrations from core to rim. Mean olivine composition is Fa20.53.2 (Fa16.4-29.5; n=17); Fe/Mn (at.): 5012. Mean low-Ca pyroxene composition is Fs20.10.9Wo2.70.3 (Fs18.1-21.4Wo2.2-3.1; n=17); Fe/Mn (at.): 2910. The mean composition of Ca-rich pyroxene is Fs18.62.1Wo28.13.9 (Fs15.0-22.3Wo21.7-34.1; n=8); Fe/Mn (at.): 287. Mean bulk composition of fine-grained interstitial material (EDX analyses; area ~50x100 m; wt%): SiO2 64.2; Al2O3 17.1; Na2O 9.4; FeO 4.2; CaO 3.2; MgO 0.5; K2O 0.8; TiO2 0.7. Based on mineral chemistry, this sample has affinities to L or H ordinary chondrites.
Price: 450 USD
Location: Riverside, California
End Time: 2025-01-16T07:34:43.000Z
Shipping Cost: 11 USD
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