What are eucrites?

What are they important for?

View a list of fine Eucrites

A few asteroids have molten not too long after there formation.

Eucrites are a very interesting class of achondrites; many finds of them are thought to have originated from Vesta.

To understand how magmas migrated, erupted, and fractionated on these mostly smaller bodies helps us to understand what causes magma composition to change in general.

Asteroids with an appr. size of that of Vesta (appr. 500km diameter) could seriously be considered not to have completely evolved magmatic processes.  Although these rocks experienced significant (postcrystallization) impact shock these materials still  contain important information about the earlier stages of asteroidal and planetary

history and formation in our solar system as well as of thermal metamorphism (Metzler et al.; Yamaguchi). Several eucrites contain glass inclusions (tiny droplets of the molten rock, silica polymorphs,cristobalite and/or tridymite) trapped within mineral grains. These inclusions preserve information about magmatic processes and other thermal history data of the material.

updated: 11/25/2009

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cumulate eucrites  Cumulate eucrites are a scientifically highly interesting meteorite group. Cumulate eucrites are mostly coarse grained and have usually a wide range in bulk element composition due to compositional differences in their mineralogy.  Cumulate eucrites are basically gabbros composed of low-Ca pyroxene and calcic plagioclase. They also usually contain minor inclusions of silica,.troilite,  phosphate, chromite,  ilmenite, free metal. Several representatives of this group are unbrecciated: like Binda, ALH 85001 . Unbrecciated cumulate eucrites do have only  a low percentage of Ni, with <0.5 wt % Ni in the free metal inclusions. Binda, e.g. is a polymict breccia (Garcia, Prinz 1978) . Several polymict eucrites display also cumulate eucrite material. The texture of unbrecciated cumulate eucrites is equigranular with spyroxene and plagioclase grains 0.5-3 mm diameter (Hess and Henderson 1949, Lovering 1975, Mittlefehldt and Lindstrom.)

The original igneous pyroxene of cumulate eucrites was pigeonite, which has subsequently undergone subsolidus exsolution of augite and, in some cases, inversion to orthopyroxene, with additional augite exsolution. Hess and Henderson (1949) determined that original pigeonite in Moore County had only partially inverted to orthopyroxene: They described four pyroxenes in Moore County; low-Ca pigeonite developed from the original igneous pigeonite by exsolution of coarse lamellae of augite, and hypersthene developed from the low-Ca pigeonite through inversion and exsolution of fine lamellae of pyroxene phases. Harlow et al. (1979) found that the original igneous pigeonite in Serra de Mage had inverted to hypersthene, with development of four types of augite exsolution during the subsolidus cooling history. Similarly, in Moama the original igneous pigeonite has exsolved augite and inverted to hypersthene (Lovering 1975a Takeda et al. 1976). Binda is the most magnesian of the cumulate eucrites, and the only one classified by Delaney et al. (1984) as an orthopyroxene-cumulate eucrite. Takeda al. (1976) have shown that the original pyroxene in Binda was a low-Ca pigeonite that exsolved augite and inverted to hypersthene. Table 30 gives representative pyroxene analyses for selected cumulate eucrites, and estimated primary pigeonite compositions are plotted in Figure 42. As is the case for all HED meteorites, plagioclase in cumulate eucrites is calcic is on average more calcic than that in basaltic eucrites. Basaltic eucrite plagioclase has compositions in the range of bytownite to anorthite, while in cumulate eucrites the plagioclase is anorthite, An91-95;. A-881394 contains unusually calcic plagioclase, An,, {Takeda et al. 1997b). The K2O contents of cumulate eucrite plagioclases are very low typically <0.1 wt %.

The blue-metallic ilmenite occurs as small grains in most cumulate eucrites . Only in Moama ilmenite could not be found (Delaney et al. ,1984).

The composition of metal in the cumulate eucrites Binda, Moama, Moore County has received only cursory study (Duke 1965, Lovering 1964, 1975).

Based on modal abundances (Delaney et al 1984) cumulate eucrites can be divided into 2 subgroups:

a) feldspathic cumulate eucrites

b) orthopyroxene cumulate eucrites

There is a small but reasonable  possibility that  this meteorite might have originated Mercury

Anom. Eucrite with Mesosiderite tendency Dho 007

Black impact melt veins and pockets are abundant.

   Thermal history: Metal phases underwent a very slow cooling! (Yamaguchi et al)

This rare type is a cumulate eucrite, - a monomict breccia derived from a magmaticrock having a gabbroic texture consisting of subhedral grains of pyroxene

and plagioclase. Accessory minerals include metal, troilite, and chromite.

Dho 007 has a variety of glass inclusions (approximately up to 10 microns in diameter) contained in plagioclase  and pyroxene  grains as well as in the form a homogeneous melt. Gas bubbles formed from shrinkage during cooling can be found in the glass. The glass inclusions occur generally in round shape.

 Highly-silicic glass inclusions in Dho 007 and diogenites

The glass inclusions in Dho 007 have highly silicic compositions and are

 depleted in alkalis as compared with those in other meteorites.

Although silicate melts can be produced by low-degree partial melting of peridotites,

the resultant melts have not highly silicic composition but only basaltic, and

contain a high concentration of incompatible elements (Kushiro, +31/; Baker et al., +33/).

The inclusions analyzed in the present study are almost pure silica and are not very rich in

incompatible elements. Thus, these inclusions appear to be produced by another

formation mechanism. Schiano et al. (+33/) suggest that silicic-rich glasses in the

Earth’s upper mantle could be generated from a very low degree of partial melting of

ma.c minerals. A dehydrogenation of nominally anhydrous ma.c minerals by heating

or depressurization has also been proposed as a possible formation mechanism .

 However, in contrast to the results reported here, formation of silica-rich

melts in clinopyroxene-bearing rocks by both mechanisms should be accompanied by

enrichments of alkali and incompatible elements. In addition, a highly silicic melt

 should react with olivine during the migration of melt, so the formation

of the present inclusions requires generation in an olivine-absent system.

A highly silicic melt can be produced in the early stages of incongruent melting of

clinopyroxene, as estimated from melting experiments of clinopyroxene . In addition, the melt generated from orthopyroxene

is expected to be lower in contents of incompatible elements than that produced from

clinopyroxene-bearing rocks such as basalt, because of low abundances of incompatible

elements in orthopyroxene as compared with clinopyroxene.

Therefore, our results are consistent with a silica-rich melt generated from the incongruent melting of olivineabsent

orthopyroxenite. For Dhofar 007, formation of the inclusions in host plagioclase

might be considered by capturing incongruent melts of orthopyroxenite from

insights into their major compositions. It remains unclear if the melting event that

formed these secondary inclusions resulted from thermal heating or from shock-induced breakdown of pyroxene.

Based on the above evidence from these inclusions, they cannot have originated

from a late stage residual melt on the parent body. 

The occurrence of these secondary glass inclusions, outlining healed fractures in a single crystal, suggests migration of melts

after the crystallization process. Although the migration of highly silicic melts generally

is considered to be di$cult because of high viscosity, the viscosity of the original

melts of the glass inclusions analyzed might have decreased because of the enrichment

in sulphur.

Consideration of the data reported above allows an interpretation of the possible

petrogenesis of these glass inclusions. First, silica-rich melt penetrated into fractures in

the host mineral. Later annealing healed the fracture and tiny droplet glass inclusions

remained. Then, the daughter minerals precipitated from the inclusion melt during

cooling, and, finally, the remaining silicic melt solidifed. By this time, the glass

inclusions were modifed to the shape of negative crystals, which were elongated along

the cleavage direction of the host mineral orthopyroxene.


Kouhei Kitazato+,, and Masanori Kurosawa-

+ Department of Earth and Planetary Science, University of Tokyo,

Hongo, Bunkyo-ku, Tokyo ++--**--

, Department of Planetary Science, Institute of Space and Astronautical Science,

Japan Aerospace Exploration Agency, Yoshinodai, Sagamihara ,,3-2/+*

- Institute of Geoscience, University of Tsukuba, Tennodai, Tsukuba -*/-2/1+

ask for fair price erich.haiderer@chello.at


noncumulate eucrites

Most noncumulate eucrites have been considered as early crustal rocks of the HED parent body. Almost all noncumulate eucrites are metamorphic rocks.

Eucrites have been classified into 7 metamorphic types mainly based on the pyroxene mineralogy [1,2]. If eucrites were metamorphosed by burial of countless lavas during crust formation, the degree of metamorphism may be directly related to the timing of eruption [2]. Therefore, there might be a correlation between the degrees of metamorphism, bulk compositions, and radiometric ages [3,4]. For geochemical study, it is essential to examine unbrecciated eucrites or monomict eucrites since some “monomict eucrites” [5] (e.g., Pasamonte and Sioux County) have been reclassified into polymict eucrites [6,7]. A881747. The observation of the broken surface indicates that A881747 is mostly (~60-80%) composed of an angular subophitic lithology set in a gray matrix. The PTS displays a subophitic texture, consisting of coarse, lath-shaped plagioclase and anhedral, irregular pyroxene. The pyroxenes have a remnant Ca-zoning with closely spaced, thick (~10 µm) augite lamellae at the rim and sparsely sapaced (~50-100 µm in width) augite lamellae (~10 µm thick) in the core (i.e., type 4 [1]). Chemical compositions of pyroxenes vary from Wo4.8En35.5 to Wo41.6En30.3. Plagioclase in this rock is compositionally zoned from An89.0Or0.59 to An78.0Or1.7, similar to type 2 eucrites (e.g., Pasamonte clast) [6]. Analytical techniques: We obtained aliquots of powdered samples that were originally prepared from

et al. [2] suggested that types 5 and 6 eucrites may have been metamorphosed at ~1000 °C for a prolonged time to homogenize the Ca-Mg in the originally zoned pyroxenes, and those of types 4 and 7, which have remnant Ca-zoning in pyroxenes, could be less metamorphosed (peak metamorphic temperature <1000 °C). The strongly recrystallized texture of eucritic granulites [2] indicates that they may have been metamorphosed comparable to or more than types 5 and 6. Thus, we tentatively classified into the following groups: group A (types 1- 3), B (types 4 and 7), C (types 5 and 6), and D (eucritic granulites). Several eucrites (e.g., Ibitira and EET90020) experienced higher temperatures. However, since the heat source of metamorphism could have been shock-related, we excluded these eucrites from this classification.


  Millibillilli, type 6 (highly thermally equilibrated) in the metamorphic sequence of  Hiroshi Takeda

Available are wonderful individuals @$14/g, and enpieces ($16/gr) from 15 - 35gr showing nice breccias: All legally exported.

Ask for best price and let us know your wishes of sizes; eric@mars.li



Stannern, type 4 in the metamorphic sequence of  Hiroshi Takeda


eucrite, polymict - Dhofar 1286

18°25′579′′N, 54°25′719′′E  Find: December 2005

Achondrite (eucrite, polymict)

History: Two pieces of meteorite weighing 898 g in total were found on a sandy surface in the desert of Oman. The distance between the fragments was about 30 m. Joined together, the fragments form an almost complete individual sample with ~10% missing.

Petrography: (Lorenz, Vernad and Brandstätter, NHMV) On the unbroken surfaces, black fusion crust is partly preserved. The meteorite is a polymict breccia consisting of fragments of medium- to coarse-grained metamorphosed gabbroic rocks and fine- to medium-grained subophitic basaltic rocks. Minor equigranular metamorphic pyroxene-feldspar rocks, melts, and melt matrix breccias are present. The rock fragments are situated in a fine-grained clastic matrix and comprise 60 vol% of the whole meteorite. Accessory minerals are troilite, chromite, ilmenite, silica, Ca phosphate, and metal Fe,Ni.

Geochemistry: Pyroxene (En35.1–62.8Wo1.8–5.7; Fe/Mn = 30) with exsolved augite (En21.1–54.2Wo21.1–38.9).

Specimens: A 20.6 g type specimen and one polished section are on deposit at Vernad. An anonymous finder holds the main mass.

Ask for best price for the slice above and let us know your wishes of sizes; eric@mars.li


DaG 995 - very unusual eucrite, partly cumulated, fresh like a Fall!! 

Found 2001 January 3

Achondrite (eucrite)

 A single stone of 56.12 g partly covered by fusion crust was found 2001 January 3 by an anonymous finder in the sand desert of Dar al Gani. Classification and mineralogy (A. Greshake and M. Kurz): has subophitic texture with plagioclase laths embedded in exsolved Ca-pyroxene, augite, and silica; several areas of the meteorite are recrystallized; plagioclase, An89.5 (range An88.4-90.6); exsolved Ca-pyroxene with pigeonite lamellae, Fs51.8-60Wo5-15.2 and augite lamellae, Fs31-34.2Wo37.3-40.5; unexsolved augite Fs30.7Wo40.6; minor phases include orthopyroxene, ilmenite and Ti-rich chromite; plagioclase contains small crystallographically orientated inclusions of augite, pigeonite, and silica; augite contains small plagioclase and Ti-rich chromite inclusions; the sample appears to be unbrecciated in thin section; low degree of shock; low degree of weathering. Main mass with anonymous finder; type specimen 11.6 g plus one polished thin section MNB.

0,2g sold; 1.2g slice sold; 1.231g slice 24x21mm $160; 3.67g endpiece with crust $430;

mostly with fresh sparling black crust

Available only through us!

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Eucrite - JaH 061

1 meteorite of 141g was found 10/2000 
S2 W1 61.1 2.5 Plag: An 89-91 20g Freiburg
ultrathin slices 1g 34x25mm $70; 1.8g $115


brecciated eucrite composed of fine-grained basalt - NWA 999

 TkW: 823 g . It is a fine-grained, low-Calzium,  eucrite

1 gram 12x14mm slice $60; BB $10


eucrite, polymict - NWA 1813 Occidental Sahara

One stone of 70 g was found winter 2001/2 in Western Sahara. Mineralogy (C. Lorenz,

Vernad): the polymict breccia consists of a number of mineral and

rock-fragments, embedded in a fine-grained clastic matrix. The lithic

clasts are coarse- to medium-grained, poikilitic and poikilo-ophitic

pyroxene-plagioclase rock clasts (~40 vol%), minor fine-grained

granoblastic pyroxene-plagioclase rock clasts (~5 vol%), melt rocks

and breccias. Mineral chemistry: pyroxene is En37.5Wo3.1 with

lamellae of En30.5Wo42.2; feldspar is An88-92. Accessory phases are

silica, chromite, ilmenite, troilite and Fe-metal. Specimens: one

section and 14g, Vernad; main mass with anonymous finder.

ask for fair price erich.haiderer@chello.at

no pairing - Available only through us!


Eucrite mon.- NWA 1895

3 fresh fragments with a tkW of 244g black fusion crust were found 2002 in Algeria TkW 244gr 21,2 Moderate Moderate 64,6 Mean An Mol % = 88.0, Range 85.1 - 92.2; O Oxygen isotopes: T13-14 d17O‰ = +1.873, d18O‰ = +3.890, D17O‰ = - 0.150;

beautiful thin slices with crust between 1 to 3grm : erich.haiderer@chello.at

  Eucrite pm.- NWA 2906

A single stone of 18 g was found early 2002 in Western Sahara. Classification and mineralogy (A. Greshake and M. Kurz): a polymict breccia composed of large lithic and mineral clasts set into a fine-grained groundmass; lithic clasts are basaltic fragments and impact melt clasts; large mineral fragments are mostly plagioclase and exsolved Ca-pyroxene; plagioclase, An83-91.5; pyroxene, Fs29.7-58.5Wo6.5-40.3; minor phases include orthopyroxene, silica, troilite, and ilmenite; low degree of shock; low degree of weathering. Main mass with anonymous finder; type specimen 3.7 g plus one polished thin section MNB.

ask for fair price erich.haiderer@chello.at


  Eucrite  - NWA2481

polymict eucrite (paired to Howardite) with a huge variety of distinct clasts;
Several eucrites of total 5009 g were found in the Western Sahara; Mineralogy: Pigeonite: Fs43.1-53.3Wo5.8-18.7; Plagioclas An87.5-92.3; Classification: Dr.A.Greshake, Humboldt University, Berlin, Germany; M.Kurz, Germany
part or complete slice, fragments or segment from $15/gr, slices 29/gr



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Partly cumulated eucrite - Northwest Africa 3075

no pairing - Available only through us!

Achondrite (eucrite); polymict breccia with basaltic, impact melt and large minerals clasts set into a more fine-grained matrix of plagioclase, pigeonite with augite exsolution lamellae, and opaque phases; some clasts show cumulate texture; plagioclase, An87(An83.4-88.2); pigeonite, Fs32.9-74.2Wo7.5-16.7; augite, Fs64.7Wo21.6; A single eucrite of 446 g completely covered by fusion crust was found in 2000 by an anonymous finder in the Western Saharan desert. Classification and mineralogy (A. Greshake and M. Kurz, MNB):

minor phases include silica, chromite, and phosphates; numerous shock veins, strong mosaicism of pyroxene, and strong undulatory extinction of plagioclase attest high degree of shock; moderate

degree of weathering. Specimens: Main mass with

anonymous finder; type specimen 20.2 g plus one polished thin

section MNB.

0.367g thin slice appr.16x12mm $28; 3.78g slice; 6,11g complete slice

ask for fair price erich.haiderer@chello.at


NWA XXX - highly metamorphized eucrite

2,521g 25x24mm max. (is more a thin endpiece) no crust €70

2,422g 24x26mm max. crust €70

11,412g 59x45mm max. some crust €220

3,106g 40x31mm max. no crust €76

1.606g 25x14mm max. no crust €43


DaG 647 - unique eucrite with 2-stage thermal history, recrystallized, fresh like a Fall!! 

Ask for best price and let us know your wishes of sizes; eric@mars.li


PTS of DaG 647


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