On Offer:  10.46g End piece of HED Achondrite unbrecciated basaltic Eucrite NWA 12932 

Dimensions: 41 mm x 38 mm x 3 mm

Official Name: NWA 12932

Found: 2016

Location: North West Africa

Observed fall: No

Description: An amazing 10.46 gram slice of unbrecciated Eucrite HED Achondrite NWA 12932 with a fine-grained mix of plagioclase and pyroxene grains in the interior.

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.

Hi, from the University of Colorado Boulder microprobe lab where we do the analysis and classification for our new meteorites.

What you get: Unbrecciated Eucrite meteorite slice as shown, membrane storage/display box, & signed Certificate of Authenticity.

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

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Northwest Africa 12932
Basic information	Name: Northwest Africa 12932      This is an OFFICIAL meteorite name. Abbreviation: NWA 12932 Observed fall: No Year found: 2016 Country: (Northwest Africa) Mass: 2.91 kg
Classification   history:	Meteoritical Bulletin:   MB 108   (2020)   Eucrite-unbr Recommended:   Eucrite-unbr     This is 1 of 148 approved meteorites classified as Eucrite-unbr.   [show all] Search for other: Achondrites, Eucrites, and HED achondrites
Comments:	Approved 21 Nov 2019
Writeup	Writeup from MB 108: Northwest Africa 12932 (NWA 12932) (Northwest Africa) Purchased: 2016 Classification: HED achondrite (Eucrite, unbrecciated) History: Purchased Nov 2016 by Dustin Dickens in Mauritania from anonymous dealer. Physical characteristics: Single stone, fusion-crusted exterior, broken surface and saw cut reveals a light colored, fine-grained mix of plagioclase and pyroxene grains. Petrography: (C. Agee, UNM) Microprobe examination of a polished mount shows an ophitic texture with approximately 60% pyroxene and 35% plagioclase. Many pyroxenes have exsolution lamellae. Minor silica and troilite observed. Geochemistry: (C. Agee, UNM) Low-Ca pyroxene Fs61.9±0.6Wo2.8±1.1, Fe/Mn=31±1, n=8; high-Ca pyroxene Fs28.2±2.1Wo43.2±2.3, Fe/Mn=31±1, n=4; plagioclase An86.7±4.1, n=6. Classification: Basaltic eucrite, equilibrated, unbrecciated. Specimens: 20.6 g including a probe mount on deposit at UNM, Dustin Dickens holds the main mass.
Data from:   MB108   Table 0   Line 0:	Place of purchase: Mauritania Date: P 2016 Mass (g): 2912 Pieces: 1 Class: Eucrite-unbr Shock stage: moderate Weathering grade: low Ferrosilite (mol%): 61.9±0.6, 28.2±2.1 Wollastonite (mol%): 2.8±1.1, 43.2±2.3 Classifier: C. Agee, UNM Type spec mass (g): 20.6 Type spec location: UNM Main mass: Dustin Dickens Comments: Field name DD-57; submitted by C. Agee, UNM