Suessite
Encyclopedia
Suessite is a rare iron silicide
mineral with chemical formula: Fe3Si. The mineral was named after Professor Hans E. Suess. It was discovered in 1982 during the chemical analysis of The North Haig olivine
pigeonite
achondrite
(ureilite
). It is a cream white color in reflected light, and ranges in size from 1 μm "blebs" to elongated grains that can reach up to 0.45 cm in length. This mineral belongs in the isometric crystal class. The isometric class has crystallographic axes that are all the same length and each of the three axes perpendicular
to the other two. It is isotropic, has a structural type of DO3 and a crystal lattice of BiF3.
, but there was no determination of the index of refraction. In plane polarized light, suessite is a reddish-brown color that shows no pleochroism
.
which is the mineral from which Suessite is formed. In this particular study, the meteorite that contained suessite contained the highest amounts of shock metamorphism
, which can be determined from the size of a shatter cone
created from the impact. This could mean that suessite is formed due to the extreme increase in temperature combined with reduction of silicate rims, shortly followed by a rapid decrease in temperature. This means that, in meteorites, the abundance of suessite can be used to identify deformation associated with shock metamorphism, which could be used to determine various characteristics of the studied meteorites.
Silicide
A silicide is a compound that has silicon with more electropositive elements.Silicon is more electropositive than carbon. Silicides are structurally closer to borides than to carbides....
mineral with chemical formula: Fe3Si. The mineral was named after Professor Hans E. Suess. It was discovered in 1982 during the chemical analysis of The North Haig olivine
Olivine
The mineral olivine is a magnesium iron silicate with the formula 2SiO4. It is a common mineral in the Earth's subsurface but weathers quickly on the surface....
pigeonite
Pigeonite
Pigeonite is a mineral in the clinopyroxene group. It has a general formula of Si2O6. The calcium cation fraction can vary from 5% to 25%, with iron and magnesium making up the rest of the cations....
achondrite
Achondrite
An achondrite is a stony meteorite that does not contain chondrules. It consists of material similar to terrestrial basalts or plutonic rocks and has been differentiated and reprocessed to a lesser or greater degree due to melting and recrystallization on or within meteorite parent bodies...
(ureilite
Ureilite
Ureilite is a rare type of stony meteorite that has a unique mineralogical composition very different from that of other stony meteorites. This dark grey or brownish meteorite type is named after the village Novy Urey , Mordovia Republic of Russia, where a meteorite of this type fell on 4 September...
). It is a cream white color in reflected light, and ranges in size from 1 μm "blebs" to elongated grains that can reach up to 0.45 cm in length. This mineral belongs in the isometric crystal class. The isometric class has crystallographic axes that are all the same length and each of the three axes perpendicular
Perpendicular
In geometry, two lines or planes are considered perpendicular to each other if they form congruent adjacent angles . The term may be used as a noun or adjective...
to the other two. It is isotropic, has a structural type of DO3 and a crystal lattice of BiF3.
Optical Properties
Suessite is an isotropic mineral, Isotropism is defined as an optical property of a mineral that stays the same from whatever direction it is observed. In thin-section microscopy, an isotropic mineral has only one refractive index. This means that light that passes through the mineral is not split into two different directions, but it passes through unchanged. Suessite, as determined from the previous definition, only has one index of refraction. When Keil, Fuchs, and Berkley first discovered the mineral they described it as having a relatively low optical reliefOptical relief
Optical relief is a concept in optical mineralogy which refers to the degree in which mineral grains stand out from the mounting medium, usually either oil with a known refractive index or Canada Balsam...
, but there was no determination of the index of refraction. In plane polarized light, suessite is a reddish-brown color that shows no pleochroism
Pleochroism
Pleochroism is an optical phenomenon in which a substance appears to be different colors when observed at different angles with polarized light.- Background :Anisotropic crystals will have optical properties that vary with the direction of light...
.
Importance of suessite
"Suessite can form under highly reducing conditions" say the scientists who discovered this mineral. Only one out of eight ureilites studied (the North Haig ureilite) by this group contained suessite. Most contained trace amounts of kamaciteKamacite
Kamacite is a mineral. It is an alloy of iron and nickel, usually in the proportions of 90:10 to 95:5 although impurities such as cobalt or carbon may be present. On the surface of Earth, it occurs naturally only in meteorites. It has a metallic luster, is gray and has no clear cleavage although...
which is the mineral from which Suessite is formed. In this particular study, the meteorite that contained suessite contained the highest amounts of shock metamorphism
Shock metamorphism
Shock metamorphism or impact metamorphism describes the effects of shock-wave related deformation and heating during impact events. The formation of similar features during explosive volcanism is generally discounted due to the lack of metamorphic effects unequivocally associated with explosions...
, which can be determined from the size of a shatter cone
Shatter cone
Shatter cones are rare geological features that are only known to form in the bedrock beneath meteorite impact craters or underground nuclear explosions...
created from the impact. This could mean that suessite is formed due to the extreme increase in temperature combined with reduction of silicate rims, shortly followed by a rapid decrease in temperature. This means that, in meteorites, the abundance of suessite can be used to identify deformation associated with shock metamorphism, which could be used to determine various characteristics of the studied meteorites.