Description: Hello, up for sale is NWA 15915, newly classified as a rare ungrouped achondrite, VERY UNIQUE with mg-rich diopside. More studies are being done now, including aging. This ultra rare endcut weighs 128.60 grams, with perfect polish to one side and very fresh black fusion crust with rollover lip. It is composed of many small crystalized fragments with Fe sulfides (daubreelite alabandite, troilite) ! Coarse grained protogranular aggregate (mean grainsize ~2 mm) composed predominantly of homogeneous, almost pure end-member diopside (with sparse, very thin exsolution lamellae of enstatite) accompanied by subordinate discrete grains of enstatite (~ 10 vol.%) and accessory daubreelite, alabandite, troilite, minor low-Ni kamacite and secondary Fe oxide. Olivine and plagioclase are absent. These specimens bear some petrologic and isotopic resemblance to Mg-rich websteritic achondrite NWA 13307 but differ in being much richer in clinopyroxene This comes with a COA card and display case. Thanks for your interest and take care. THIS ENDCUT WAS PURCHASED FROM MARK LYON. ***Ungrouped, Mg-rich diopside and speculation is going on. The age of this mysterious material is still being analysed. Many strange metal-like spherules inside translucent crystals.** Name: Northwest Africa 15915 This is an OFFICIAL meteorite name. Abbreviation: NWA 15915 Observed fall: No Year found: 2023 Country: Algeria Mass: 2.84 kg Northwest Africa 15915 (NWA 15915) Algeria Purchased: 2023 Feb Classification: Ungrouped achondrite History: Purportedly found near Aougrout, Algeria. The largest stone was purchased from the finder by Jaouad Chaoui in October 2022 and subsequently cut and sold in two portions to Jay Piatek and Ben Hoefnagels in February 2023. Three additional stones found at the same location were purchased by Mark Lyon in May 2023 from Jaouad Chaoui. Physical characteristics: The pale yellowish stones (1359, 808, 650, and 26 g) are partially coated with black fusion crust. The very fresh interiors are predominantly beige in color and somewhat friable. Petrography: (A. Irving, UWS, and J. Boesenberg, BrownU) Coarse grained protogranular aggregate (mean grainsize ~2 mm) composed predominantly of homogeneous, almost pure end-member diopside (with sparse, very thin exsolution lamellae of enstatite) accompanied by subordinate discrete grains of enstatite (~ 10 vol.%) and accessory daubreelite, alabandite, troilite, minor low-Ni kamacite and secondary Fe oxide. Olivine and plagioclase are absent. Geochemistry: Diopside (Fs0.0-0.1Wo37.5-43.3, N = 16), enstatite (Fs0.1-0.3Wo0.5-3.2, N = 9). Oxygen isotopes (D. Ibarra, BrownU): analysis of an acid-washed subsample by laser fluorination gave, respectively 17O 3.369, 18O 6.470, 17O -0.035 per mil (TFL slope value = 0.526). Classification: Achondrite (ungrouped, Mg-rich diopsidite). These specimens bear some petrologic and isotopic resemblance to Mg-rich websteritic achondrite NWA 13307 but differ in being much richer in clinopyroxene. Although the 17O values for both of these Mg-rich specimens are identical, the 18O value for this specimen is higher by 1 per mil. relative to NWA 13307. Specimens: 23.8 g including one polished thin section at UWB; portions of the 1359 g main mass are held separately by Mr. J. Piatek (645 g) and Mr. B. Hoefnagels (650 g); other stones of 808 g, 650 g and 26 g are held by Mr. M. Lyon. Data from: MB112 Table 0 Line 0: Place of purchase:Tucson Date:P 2023 Feb Mass (g):2843 Pieces:4 Class:Achondrite-ung Shock stage:low Weathering grade:low Ferrosilite (mol%):0.10.1; 0.1-0.3 Wollastonite (mol%):42.2-43.3; 0.5-0.7 Classifier:A. Irving, UWS, and J. Boesenberg, BrownU Type spec mass (g):23.8 Type spec location:UWB Main mass:J. Piatek/B. Hoefnagels Comments:Work names JC43 and BH280; submitted by A. Irving
Price: 36000 USD
Location: Riverside, California
End Time: 2024-11-28T05:35:06.000Z
Shipping Cost: 9 USD
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