Elgoresyite, first discovered during the crystallographic study of the
Suizhou meteorite
The Suizhou meteoriteXiande Xie, Ming Chen.
Suizhou Meteorite: Mineralogy and Shock Metamorphism.
ISSN 2194-3176
ISSN 2194-3184 (electronic)
(eBook)
DOI 10.1007/978-3-662-48479-1
Library of Congress Control Number: 2015950454
Springer-Verlag 2016 ...
, is a naturally occurring, high-pressure iron-magnesium silicate mineral. High-pressure poly morphs of magnesium silicates have been rarely discovered on Earth, due to retrograding as they ascend to the surface. It is named after
Ahmed El Goresy
Ahmad ( ar, أحمد, ʾAḥmad) is an Arabic male given name common in most parts of the Muslim world. Other spellings of the name include Ahmed and Ahmet.
Etymology
The word derives from the root (ḥ-m-d), from the Arabic (), from the ve ...
.
Occurrence
Currently, Elgoresyite has only been known to occur in the shock-induced melt veins of the Suizhou meteorite. These veins are ~300 μm in thickness.It is found in association with the minerals
ringwoodite,
olivine,
tetragonal ringwoodite
In crystallography, the tetragonal crystal system is one of the 7 crystal systems. Tetragonal crystal lattices result from stretching a cubic lattice along one of its lattice vectors, so that the cube becomes a rectangular prism with a square ...
,
taenite, and MgSiO
3 rich glass.
Appearance and Properties
Physical properties such as color, luster, streak, hardness, tenacity, cleavage, fracture, and density could not be determined due to small grain size of the only known sample available. Optical properties as well were not able to be determined for this same reason. Density (calc) however is 4.315 g/cm
3. This was based on the empirical formula and single-crystal XRD data.
Chemical Properties
The empirical formula is (Mg
3.38Si
1.95Fe
2+1.60Al
0.05Na
0.03Ca
0.02)
Σ = 7.03O
9. The simplified and ideal chemical formula is (Mg,Fe,Si)
7O
9.
Crystallography
The crystal system is
monoclinic, and the
space group is ''C''2/''m'' (#12). The
unit cell parameters are :a = 9.397(2) Å, b = 2.763(1) Å, c = 11.088(3) Å, β = 94.25(2)°, volume V =287.10(14) Å
3, and number of formulas per unit cell, Z = 2.
References
{{Reflist
Wikipedia Student Program
Monoclinic minerals