On Offer: 24.4 gram complete beautiful slice of NWA12338 achondrite-ung

Approximate Dimensions: 109mm x 68.6mm x 2mm

Classification: Achondrite Ungrouped - this is an ungrouped achondrite from an unknown differentiated parent body.

Origin: Unkown

Description: Beautiful slice of an amazing ungrouped achondritic meteorite. 

The HED Meteorite Clan: petrological evidence and data from NASA's Dawn mission indicate that nearly monomineralic ultramafic orthopyroxenite, olivine-bearing, and the much more rare harzburgitic, and dunite diogenites formed alongside each other. They likely originated as cumulates within localized magma chambers (plutons) situated across Vesta's lower crust and the lower-crust/upper-mantle transition zone. While the eucrites represent more evolved plagioclase rich mafic upper to middle zone crustal material. The howardites were formed by impact mixing of the diogenitic and eucritic material both in situ and during ejection events.

The HED meteorites are so named for the three types of meteorites that comprise the group; Howardite, Eucrite and Diogenite. The Eucrite and Diogenite are meteorites with distinct chemistries, while the Howardite is a mix of the eucritic and diogenitic material. The HEDs are differentiated achondritic meteorites, thought to originate from the large differentiated asteroid 4 Vesta. Vesta is one of the only asteroids visible with the naked eye and low powered telescopes.

The Vesta parent body origin for the HED clan of meteorites is considered to have been conclusively established for many years. However, the late Dr. John Wasson, a planetary science researcher from UCLA had long held that the HED meteorite clan originated from another unknown Vesta-like asteroid that was blown apart long ago. This is because we also find a class of iron meteorites with nearly identical oxygen isotopes as the HED clan. This along with other research lead Dr. Wasson to conclude the HED clan of meteorites come from another differentiated V-type asteroid that was in a cataclysmic collision liberating part or all of its metal core along with the HED meteorites.

However, this hypothesis does not necessarily rule out the possibility that a "reaccreted" Vesta and the smaller V-type asteroids collectively known as Vestoids along with the HED meteorites and the isotopically paired irons were all once part of a much larger dwarf planet prior to a massive collision with another large body. While most researchers consider the case mostly closed on this debate, the paradox of isotopically paired core metal raised by Dr. Wasson's hypothesis has not been resolved. This leaves some to speculate that perhaps we still have more to learn about this fascinating clan of achondrite meteorites and even Vesta itself.

What you get: meteorite specimen as shown & signed Certificate of Authenticity.

We offer a 100% no questions asked 30 day return policy.

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Northwest Africa 12338
Basic information	Name: Northwest Africa 12338      This is an OFFICIAL meteorite name. Abbreviation: NWA 12338 Observed fall: No Year found: 2016 Country: (Northwest Africa) Mass: 1127 g
Classification   history:	Meteoritical Bulletin:     (2018)   Achondrite-ung Recommended:   Achondrite-ung     This is 1 of 100 approved meteorites classified as Achondrite-ung.   [show all] Search for other: Achondrites, Ungrouped achondrites
Comments:	Approved 11 Dec 2018
Writeup	Writeup from MB 107: Northwest Africa 12338 (NWA 12338) (Northwest Africa) Purchased: 2016 Nov Classification: Ungrouped achondrite Physical characteristics: The repository specimen has a brown fusion crust surface and a light-gray, fresh interior. Petrography: (Z.G. Guo, UWO) This is an unbrecciated basaltic meteorite with fine-grained ophitic texture including ~100 μm-sized clinopyroxene (~55%), and 100-500 μm-sized plagioclase (~35%). Plagioclase is not acicular, as usually found in eucrites, but instead is interstitial between clinopyroxene crystals. Olivine (~5%) is found as ~100 μm individual crystals. It has a low content (<1%) of metal (partially weathered), chromite and troilite. Undulatory (up to mosaic) extinction is observed in plagioclase, with silica veinlets, which indicate a moderate shock stage. Geochemistry: (EMPA, Z.G. Guo and M. Beauchamp, UWO) Olivine Fa70.0±0.2, Fe/Mn=44±1 (n=10); pigeonite Fs40.5±3.3Wo10.6±4.1, Fe/Mn=30±1 (n=20); plagioclase An89.1±1.4 (n=10); Bulk chemistry (INAA, R. Korotev, WashU) Na2O 0.495%, CaO 10.2%, FeO 15.3%, and (all in ppm) Cr 3043, Co 16, Sr 92, Ba 19, La 1.05, Sm 0.74, Hf 0.52, Th 0.10, and U 0.16. (laser fluorination oxygen isotope analyses, A. Alexandre; L. Webb, UWO) acid-washed bulk rock powder Δ17O=-0.18±0.01, δ17O=1.980±0.203, δ18O=4.16±0.37 (n=2). Classification: Achondrite, ungrouped. This meteorite is an anomalous eucrite-like basaltic meteorite similar to other specimens which have been found to diverge from the HED oxygen mass fractionation line (similarly to PCA 91007 and Pasamonte, and significantly above the HED line). It has geochemical characteristics of eucrites for major element mineral compositions, and of cumulate eucrites for bulk trace element chemistry. But its mineral sssemblage with the presence of igneous olivines, texture, and its oxygen isotopic composition indicate a different parent body from HED, thus an ungrouped achondrite classification. Specimens: 24.0g at UWO including a probe mount.
Data from:   MB107   Table 0   Line 0:	Place of purchase: Erfoud, Morocco Date: P 2016 Nov Mass (g): 1126.5 Pieces: 1 Class: Achondrite-ung Shock stage: moderate Weathering grade: low Fayalite (mol%): 70.0±0.2 (N=10) Ferrosilite (mol%): 40.5±3.3 (N=20) Wollastonite (mol%): 10.6±4.1 (N=20) Classifier: Z.G. Guo, UWO Type spec mass (g): 24.0 Type spec location: UWO Main mass: S. Tutorow Comments: G688; submitted by A. Bouvier
Plots:	O isotopes: