Elgoresyite

Last updated
Elgoresyite
General
Category silicate mineral
Formula
(repeating unit)
(Mg,Fe)5Si2O9
IMA symbol Ego [1]
Strunz classification 09.
Crystal system Monoclinic
Space group C2/m
Unit cell a = 9.397  Å, b = 2.763 Å
c = 11.088 Å;
β=94.25°; Z = 2
Identification
Colorundetermined
Crystal habit subhedral
Cleavage undetermined
Fracture undetermined
Tenacity undetermined
Mohs scale hardnessundetermined
Luster undetermined
Streak undetermined
Diaphaneity Transparent
Density 4.315 g/cm3
Optical propertiesundetermined
Refractive index (n=Kc*D+1) is 1.95
Melting point ~2000K at ~23 GPa
References [2]

Elgoresyite, first discovered during the crystallographic study of the Suizhou meteorite, 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. [3]

Contents

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, taenite, and MgSiO3 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/cm3. This was based on the empirical formula and single-crystal XRD data.

Chemical properties

The empirical formula is (Mg3.38Si1.95Fe2+1.60Al0.05Na0.03Ca0.02)Σ = 7.03O9. The simplified and ideal chemical formula is (Mg,Fe,Si)7O9.

Crystallography

The crystal system is monoclinic, and the space group is C2/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) Å3, and number of formulas per unit cell, Z = 2.

Related Research Articles

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The mineral olivine is a magnesium iron silicate with the chemical formula (Mg,Fe)2SiO4. It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers quickly on the surface. For this reason, olivine has been proposed as a good candidate for accelerated weathering to sequester carbon dioxide from the Earth's oceans and atmosphere, as part of climate change mitigation. Olivine also has many other historical uses, such as the gemstone peridot, as well as industrial applications like metalworking processes.

<span class="mw-page-title-main">Wollastonite</span> Single chain calcium inosilicate (CaSiO3)

Wollastonite is a calcium inosilicate mineral (CaSiO3) that may contain small amounts of iron, magnesium, and manganese substituting for calcium. It is usually white. It forms when impure limestone or dolomite is subjected to high temperature and pressure, which sometimes occurs in the presence of silica-bearing fluids as in skarns or in contact with metamorphic rocks. Associated minerals include garnets, vesuvianite, diopside, tremolite, epidote, Plagioclase feldspar, pyroxene and calcite. It is named after the English chemist and mineralogist William Hyde Wollaston (1766–1828).

<span class="mw-page-title-main">Forsterite</span> Magnesium end-member of olivine, a nesosilicate mineral

Forsterite (Mg2SiO4; commonly abbreviated as Fo; also known as white olivine) is the magnesium-rich end-member of the olivine solid solution series. It is isomorphous with the iron-rich end-member, fayalite. Forsterite crystallizes in the orthorhombic system (space group Pbnm) with cell parameters a 4.75 Å (0.475 nm), b 10.20 Å (1.020 nm) and c 5.98 Å (0.598 nm).

<span class="mw-page-title-main">Enstatite</span> Pyroxene: magnesium-iron silicate with MgSiO3 and FeSiO3 end-members

Enstatite is a mineral; the magnesium endmember of the pyroxene silicate mineral series enstatite (MgSiO3) – ferrosilite (FeSiO3). The magnesium rich members of the solid solution series are common rock-forming minerals found in igneous and metamorphic rocks. The intermediate composition, (Mg,Fe)SiO
3
, has historically been known as hypersthene, although this name has been formally abandoned and replaced by orthopyroxene. When determined petrographically or chemically the composition is given as relative proportions of enstatite (En) and ferrosilite (Fs) (e.g., En80Fs20).

<span class="mw-page-title-main">Rhodonite</span> Single chain manganese inosilicate (MnSiO3)

Rhodonite is a manganese inosilicate, with the formula (Mn, Fe, Mg, Ca)SiO3, and member of the pyroxenoid group of minerals, crystallizing in the triclinic system. It commonly occurs as cleavable to compact masses with a rose-red color (its name comes from Ancient Greek ῥόδον (rhódon) 'rose'), often tending to brown due to surface oxidation. The rose-red hue is caused by the manganese cation (Mn2+).

<span class="mw-page-title-main">Oldhamite</span> Rocksalt group, sulfide mineral

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<span class="mw-page-title-main">Pyroxferroite</span>

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<span class="mw-page-title-main">Chloritoid</span>

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2
Al
4
Si
2
O
10
(OH)
4
. It occurs as greenish grey to black platy micaceous crystals and foliated masses. Its Mohs hardness is 6.5, unusually high for a platy mineral, and it has a specific gravity of 3.52 to 3.57. It typically occurs in phyllites, schists and marbles.

In inorganic chemistry, mineral hydration is a reaction which adds water to the crystal structure of a mineral, usually creating a new mineral, commonly called a hydrate.

<span class="mw-page-title-main">Wadsleyite</span> Mineral thought to be abundant in the Earths mantle

Wadsleyite is an orthorhombic mineral with the formula β-(Mg,Fe)2SiO4. It was first found in nature in the Peace River meteorite from Alberta, Canada. It is formed by a phase transformation from olivine (α-(Mg,Fe)2SiO4) under increasing pressure and eventually transforms into spinel-structured ringwoodite (γ-(Mg,Fe)2SiO4) as pressure increases further. The structure can take up a limited amount of other bivalent cations instead of magnesium, but contrary to the α and γ structures, a β structure with the sum formula Fe2SiO4 is not thermodynamically stable. Its cell parameters are approximately a = 5.7 Å, b = 11.71 Å and c = 8.24 Å.

<span class="mw-page-title-main">Ringwoodite</span> High-pressure phase of magnesium silicate

Ringwoodite is a high-pressure phase of Mg2SiO4 (magnesium silicate) formed at high temperatures and pressures of the Earth's mantle between 525 and 660 km (326 and 410 mi) depth. It may also contain iron and hydrogen. It is polymorphous with the olivine phase forsterite (a magnesium iron silicate).

<span class="mw-page-title-main">Osumilite</span>

Osumilite is a very rare potassium-sodium-iron-magnesium-aluminium silicate mineral. Osumilite is part of the milarite group of cyclosilicates.

Akimotoite is a rare silicate mineral in the ilmenite group of minerals, with the chemical formula (Mg,Fe)SiO3. It is polymorphous with pyroxene and with bridgmanite, a natural silicate perovskite that is the most abundant mineral in Earth's silicate mantle. Akimotoite has a vitreous luster, is colorless, and has a white or colorless streak. It crystallizes in the trigonal crystal system in space group R3. It is the silicon analogue of geikielite (MgTiO3).

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<span class="mw-page-title-main">Dollaseite-(Ce)</span> Epidote supergroup, sorosilicate mineral

Dollaseite-(Ce) is a sorosilicate end-member epidote rare-earth mineral which was discovered by Per Geijer (1927) in the Ostanmossa mine, Norberg district, Sweden. Dollaseite-(Ce), although not very well known, is part of a broad epidote group of minerals which are primarily silicates, the most abundant type of minerals on earth. Dollaseite-(Ce) forms as dark-brown subhedral crystals primarily in Swedish mines. With the ideal chemical formula, CaREE3+
Mg
2
AlSi
3
O
11
,(OH)F
, dollaseite-(Ce) can be partially identified by its content of the rare earth element cerium.

<span class="mw-page-title-main">Jimthompsonite</span>

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References

  1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi: 10.1180/mgm.2021.43 . S2CID   235729616.
  2. Bindi, L., et al., 2021, Discovery of Elgoresyite, (Mg,Fe)5Si2O9: Implications for Novel Iron-Magnesium Silicates in Rocky Planetary Interiors (accessed November,December 2021).<https://pubs.acs.org/doi/abs/10.1021/acsearthspacechem.1c00157>
  3. "Ahmed el Goresy (1934-2019)".