The specimen offered here is a polished endcut of the martian meteorite NWA 12965
This is the Main Mass of this meteorite, the largest specimen in existence with 29.51g on the original 75.1g prior to cutting for analysis;
It comes in a dispaly wallet, with a print of the Meteoritical Society Database, hand signed by the referenced original owner (Fabien Kuntz - WWMeteorites Team).
Composed of Clinopyroxene and Maskeylinite, this basaltic rock is lacking olivine, as result of a fractionnal crystalisation of a magma (the olivines crystalised first, then the remainig liquid crystalised later, at lower temperatur, as pyroxene + feldspar)
So NWA 12965 belongs to the MAFIC Shergottites (moderate in Magnesian and Ferrous minerals), and is an evolved shergottite (lately solidified in the crystalisation sequence), shergottite.
*Maskeylinite : Maskelynite is a glassy material found in some meteorites. Similar in composition to plagioclase feldspar, the glass is formed by the quenching of dense mineral melts produced by higher-pressure shock waves.
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About NWA 12965, on the Meteoritical Bulletin :
Physical characteristics: Single stone without fusion crust
Petrography: (J. Gattacceca, CEREGE) Igneous rock with sub-ophitic texture. Typical grain size 800 µm. Main minerals are strongly zoned pyroxene and maskelynite. Pyroxene has lobate contacts with plagioclase. Opaque minerals are iron oxides and pyrrhotite to 200 µm.
Geochemistry: Pyroxene Fs37.9±5.6Wo31.0±2.0, range Fs27.0-45.3Wo32.5-27.6, FeO/MnO=36.6±2.7 (n=12). Maskelynite An54.8±1.1Ab43.3±1.4Or1.9±0.4 (n=7).
Classification: Martian (Shergottite)
Specimens: Type specimen at CEREGE. Main mass with Kuntz.
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- Kristallform/ Art Meteorit
- Martian Meteorite - Shergottite NWA 12965, Igneous Rock mit subophitischer Textur - MAIN MASS
- 29.51 g
- Herkunft (Land)