Esseneit

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Esseneit
General and classification
other names

IMA 1985-048

chemical formula CaFe 3+ AlSiO 6
Mineral class
(and possibly department) 		Silicates and Germanates
System no. to Strunz
and to Dana 		9.DA.15 ( 8th edition : VIII / F.01)
65.01.03a.06
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Space group C 2 / c (No. 15)Template: room group / 15
Lattice parameters a  = natural: 9.79 (2); synthetic: 9.783 (3)  Å ; b  = natural: 8.822 (9); synthetic: 8.787 (2) Å; c  = natural: 5.37 (1); synthetic: 5.372 (3) Å
α  = 90 °; β  = natural: 105.81 (9) °; synthetic: 105.82 (3) °; γ  = 90 °
Formula units Z  = 4
Physical Properties
Mohs hardness 6th
Density (g / cm 3 ) natural: 3.54; synthetic: 3.692
Cleavage {110}
colour natural: red-brown, synthetic: light yellow
Line color White
transparency transparent
shine Glass gloss
radioactivity -
magnetism -
Crystal optics
Refractive indices n α  = natural: 1.795 (5); synthetic: 1.855 (5)
n β  = natural: 1.815 (5)
n γ  = natural: 1.825 (5); synthetic: 1,873 (5)
Birefringence δ = 0.02
Optical character biaxial negative
Axis angle 2V = 77 (5) °
Pleochroism lemon yellow - apple green

The mineral Esseneit is a very rare chain silicate from the pyroxene group with the idealized chemical composition CaFe 3+ AlSiO 6 .

Essenite crystallizes with monoclinic symmetry and forms red-brown prismatic crystals 2-8 mm in length.

Esseneit is formed under oxidizing conditions at temperatures above ~ 1000 ° C and low pressure in iron-rich calcium silicate rocks. The type locality is the Durham Ranch Paralava ( Wyoming , USA), a molten by a natural charcoal fire sediment in the Esseneit together with anorthite , Melilith and magnetite - Hercynit - mixed crystals occurs.

Etymology and history

Green Fassait from Toal de la Foia, Monti Monzoni in the Fassa Valley , Trentino , Italy

Pyroxenes containing aluminum and Fe 3+ have been known under the names Fassait and Salit since the beginning of the 19th century. Initially red-brown zeolites from the Fassa valley were called Fassait , but Abraham Gottlob Werner introduced the name Fassait in 1817 for leek to dark green pyroxenes from the Fassa valley , which are characterized by their well-developed [110] prismatic surfaces.

The characteristic contents of aluminum and ferrous iron (Fe 3+ ) without corresponding contents of sodium were proven 60 years later by Cornelio August Doelter through the first chemical analyzes of these facades, which took into account the two oxidation states of the iron. As a result, the name Fassait was extended to all aluminum and Fe 3+ -containing, low-sodium calcium pyroxene from metamorphic sand-lime bricks.

Since the beginning of the 20th century, the maximum levels of trivalent cations of diopside have been explored experimentally. E. R Segnit e.g. B. from the University of Cambridge synthesized diopside with 8% by weight Fe 2 O 3 in 1953 and Ken-ichi Hijikata synthesized diopside (CaMgSi 2 O 6 ) - Esseneite (CaFe 3+ AlSiO 6 ) - mixed crystals over the in 1968 at the University of Hokkaidō entire composition range.

Diopsids with ever higher Fe and Al contents have also been found in natural occurrences. In 1956, Knopf & Lee described a facade made of a spinel-containing, metamorphic limestone, in which 0.463 atoms per formula unit (apfu) Si were replaced by Al, and Donald R. Peacor described the structure of a pyroxene from a carbonatite with 0.494 apfu Al on the silicon position in 1967. In 1977 S. Gross documented a Fassaite made of a pyroxen wollastonite - anorthite - rock of the pyrometamorphic Hatrurim formation near Tarqumiya (Palestina) with 0.6 apfu Al on the Si position and 0.41 apfu Fe 3+ .

Pyroxenes with a composition close to the final link composition CaFe 3+ AlSiO 6 were first described in 1987 by Michael A. Cosca and Donald R. Peacor in Durham Ranch Paralava from Wyoming, USA. They named the new mineral after its discoverer Dr. Eric J. Essene , Professor at the University of Michigan in recognition of his numerous contributions to mineralogy and mineral balances.

The mineral name Fassait was discredited in 1989 by the Commission on New Minerals and Mineral Names (CNMMN) of the International Mineralogical Association (IMA).

classification

In the structural classification of the International Mineralogical Association (IMA) Esseneit belongs together with pyroxene , Burnettit , Davisit , diopside , Petedunnit , Grossmanit , Hedenbergit , Johannsenite , Kushiroit and Tissintit to Kalziumpyroxenen in pyroxene .

The 9th edition of Strunz's mineral systematics, which has been in effect since 2001 and has so far been used by the IMA, also assigns Esseneit to the class of "silicates and germanates" and there in the department of "chain and band silicates (inosilicates)". This section is further subdivided according to the type of chain formation, so that the mineral is classified according to its structure in the sub-section “Chain and band silicates with 2-periodic single chains Si2O6; Pyroxene family "can be found, where together with augite, diopside, petedunnite, hedenbergite and johannsenite, the" Ca-clinopyroxene, diopside group "with the system no. 9.DA.15 forms.

In the outdated, but still in use 8th edition of the mineral classification according to Strunz , the Esseneit belonged to the mineral class of "silicates and germanates" and there to the department of "chain silicates and band silicates (inosilicates)", where it belonged together with aegirine , augite, petedunnite, hedenbergite , Jadeit , Jervisit , Johannsenite, kanoite , clino-enstatite , Klinoferrosilit , Kosmochlor , Namansilit , Natalyit , omphacite , pigeonite and spodumene the "pyroxene group, subgroup clinopyroxene" with the system number. VIII / F.01 .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Esseneit to the class of "silicates and Germanates" and there in the department of "chain silicate minerals". Here it is together with diopside, hedenbergite, augite, johannsenite, petedunnite and davisite in the group of " C 2 / c clinopyroxene (Ca-clinopyroxene)" with system no. 65.01.03a can be found in the subsection " Chain Silicates: Simple unbranched chains, W = 1 with chains P = 2 ".

Chemism

Esseneit with the idealized composition [M2] Ca [M1] Fe 3+ [T] (SiAl) O 6 is the iron - aluminum analog of diopside ( [M2] Ca [M1] Mg [T] Si 2 O 6 ), where [M2], [M1] and [T] are the positions in the pyroxene structure.

The composition of Esseneit from the type locality is

  • [M2] (Ca 1.01 Na 0.01 ) [M1] (Fe 3+ 0.73 Al 0.04 Mg 0.16 Fe 2+ 0.02 Ti 0.03 ) [T] (Si 1.91 Al 0.81 ) O 6 .

The deviations from the ideal composition are essentially due to the following rows of mixed crystals . On the one hand, Fe 3+ on the [M1] positions is replaced by Al 3+ , corresponding to the exchange reaction

on the other hand, Fe 3+ is replaced by coupled substitutions by Mg 2+ , Fe 2+ or Ti 4+

  • [M1] Fe 3+ + [T] Al 3+ = [M1] Mg 2+ + [T] Si 4+ ( diopside )
  • [M1] Fe 3+ + [T] Al 3+ = [M1] Fe 2+ + [T] Si 4+ ( hedenbergite )
  • [M1] Fe 3+ + [T] Si 4+ = [M1] Ti 4+ + [T] Al 3+

The contents of titanium pyroxene do not exceed 18% by weight and no pyroxenes have been found in nature whose composition is dominated by the Ti 4+ end member CaTiAl 2 O 6 .

Up to a quarter of the calcium position M2 can be unoccupied, according to the exchange reaction

  • [M2] Ca 2+ + 2 [T] Al 3+ = [M2] □ + 2 [T] Si 4+

Crystal structure

Esseneit crystallizes with monoclinic symmetry in the space group C 2 / c (space group no. 15) with 4 formula units per unit cell . The natural mixed crystal from the type locality has the lattice parameters a  = 9.79  Å , b  = 8.822 Å, c  = 5.37 Å and β = 105.81 °. The lattice parameters of the synthetic end  link are a = 9.783 Å, b  = 8.787 Å, c  = 5.372 Å and β = 105.82 °. Template: room group / 15

The structure is that of clinopyroxene . Silicon (Si 4+ ) and aluminum (Al 3+ ) occupy the tetrahedral T-position surrounded by 4 oxygen ions, calcium (Ca 2+ ) occupies the octahedral M2 position surrounded by 6 oxygen and iron (Fe 3+ ) occupies the octahedral position coordinated M1 position. The distribution of iron and aluminum is highly ordered even at high temperatures above 1000 ° C. In synthetic essenite, around 10% of the Fe 3+ occupies the tetrahedral position, with correspondingly large Al contents on M1. In natural essenite, Cosca and Peacor did not find any Fe 3+ on the silicon position, which they explain with slower cooling and an order of aluminum and iron that began.

Education and Locations

Esseneit bar is stable at high temperatures even at 1 and is mined only at pressures above 40-45 kbar and 1100-1500 ° C to grossularreichen garnet and hematite oxide.

Linopyroxenes which are rich in nutrients crystallize from SiO 2 -unsaturated magmas or form metamorphically at low pressure and temperatures around 1000 ° C by pyrometamorphism of calcareous sediments .

Pyrometamorphosis

The Esseneit type locality is a paralava, a sediment melted by a natural coal fire, which emerges 25 km south of Gillette in Campbell County (Wyoming) , Wyoming , USA. Esseneit is found here together with anorthite , melilite , magnetite - hercynite - mixed crystals and glass .

In the pyrometamorphic Hatrurim Formation, food-rich clinopyroxene is found near Tarqumiya north of Hebron in the West Bank , Palestinian Territories . Accompanying minerals here are anorthite, wollastonite , gehlenite and, as an inclusion, magnetite.

Similar mineral parageneses are formed in the spoil heaps of coal mining, if they have been pyrometamorphically changed in fires.

Skarne

Relict esseneit- and kushiroite -dominated clinopyroxene with diopside contents of sometimes less than 30 mol% and 39 mol% esseneit have been described from the grossular - wollastonite endoscarnen of Cornet Hill in the Magureaua Vaţei area near Vaţa Bai in the Apuseni Mountains , Romania . They appear as small inclusions in wollastonite, along with kalsilite .

Essenite-rich clinopyroxenes have been described from the rocks of Colle Fabbri in the province of Perugia , Umbria , Italy . In the melilithite digested there , the diopsy-rich clinopyroxenes contain 25-30 mol% essenite and occur together with wollastonite, melilite, leucite , kalsilite , anorthite, zoned Ti-Garnet , perovskite , spinel and apatite . In the contact metamorphic altered pelithic sediments, the zoned clinopyroxenes show up to 44 mol% essenite in their edge areas. Accompanying minerals here are anorthite and wollastonite in a basic mass of glass, Fe-rich clinopyroxene, magnetite, potassium feldspar , spinel, titanite and sulfides.

use

Naturally occurring essenite is very rare and has no economic significance.

Essenite is of technical importance as a component of glass ceramics that can be obtained from industrial dusts such as fly ash , grinding dust or red mud . These essenite glass ceramics are very hard, have a high flexural strength and are chemically very stable, which makes them interesting for some technical applications.

Web links

Individual evidence

  1. ↑ Esseneit. In: IMA Database of Mineral Properties
  2. ↑ a b c d e f g h i j k l m n o p q r s t u v w x Michael A. Cosca, Donald R. Peacor: Chemistry and structure of esseneite (CaFe3 + AlSiO6), a new pyroxene produced by pyrometamorphism . In: American Mineralogist . tape 72 , 1987, pp. 148–156 ( rruff.info [PDF; 1,2 MB ; accessed on November 24, 2018]).
  3. ↑ a b c Ken-ichi Hijikata: Unit-cell Dimensions of the Clinopyroxenes Along the Join CaMgSi_2O_6-CaFe ^ <3+> AlSiO_6 . In: Journal of the Faculty of Science, Hokkaido University. Series 4, Geology and mineralogy . tape 14 , no. 2 , 1968, ISSN  0018-3474 , p. 149–158 ( hdl.handle.net [PDF; 420 kB ; accessed on November 24, 2018]).
  4. ↑ a b c d e Ken-ichi Hijikata, Kosuke Onuma: PHASE EQUILIBRIA OF THE SYSTEM CaMgSi2O6-CaFe3 + AISiO6 IN AIR . In: J Jap Assoc Mineral Petrol Econ Geol . tape 62 , 1969, p. 209–217 ( jstage.jst.go.jp [PDF; 412 kB ; accessed on November 24, 2018]).
  5. ^ Georg August Bertele: Handbook of Minerography of Simple Fossils . for the use of his lectures. Joseph Attenkofer, Landshut 1804, p. 183 ( books.google.de in the Google book search).
  6. ↑ C. Doelter: VI. Contributions to the mineralogy of the Fassa and Fleimser Thales . In: Mineralogical messages . 1877, p. 65–82 ( forgottenbooks.com [PDF; 34.5 MB ; accessed on November 25, 2018]).
  7. ↑ Cornelio August Doelter with the participation of numerous colleagues: Handbuch der Mineralchemie . Ed .: Cornelio August Doelter. Volume II First Half: Silicates . Springer, Berlin, Heidelberg 1914, p. 558 , doi : 10.1007 / 978-3-642-49866-4 ( books.google.de in the Google book search).
  8. ↑ CE Tilley, HCG Vincent: Aluminous Pyroxenes in Metamorphosed Limestones . In: Geological Magazine . tape 75 , no. 2 , 1938, p. 81-86 , doi : 10.1017 / S0016756800089317 ( cambridge.org ).
  9. ^ ER Segnit: Some data on synthetic aluminous and other pyroxenes. In: Mineralogical Magazine . tape 30 , 1953, pp. 218–223 ( minersoc.org [PDF; 389 kB ; accessed on November 26, 2018]).
  10. ^ Adolph Knopf, Donald E. Lee: Fassaite from Near Helena, Montana . In: American Mineralogist . tape 42 , 1956, pp. 73-77 ( minsocam.org [PDF; 334 kB ; accessed on November 26, 2018]).
  11. ^ Donald R. Peacor: Refinement Of The Crystal Structure Of a Pyroxene Of Formula M1 M2 (Si1.5Al0.5) O6 . In: American Mineralogist . tape 52 , 1967, p. 31–41 ( minsocam.org [PDF; 746 kB ; accessed on November 26, 2018]).
  12. ↑ a b Subcommite on Pyroxenes, CNMMN; Nobuo Morimoto: Nomenclature of Pyroxenes . In: The Canadian Mineralogist . tape 27 , 1989, pp. 143–156 ( mineralogicalassociation.ca [PDF; 1.6 MB ; accessed on November 11, 2018]).
  13. ↑ a b Masahide Akasaka: Clinopyroxene on the join CaMgSi2O6 CaFe3 + AlSiO6 -CaTiAl2O6 at low oxygen fugacity . In: Journal of Earth System Science . tape 99 , no. 1 , 1990, p. 39–48 ( researchgate.net [PDF; 3.0 MB ; accessed on November 30, 2018]).
  14. ↑ a b Masahide Akasaka, Kosuke Onuma: Study of the System CaMgSi2O6-CaFe ^ [3+] AlSiO6-CaAl2SiO6-CaTiAl2O6: III. The Join CaMgSi2O6-CaFe ^ [3+] AlSiO6-CaTiAl2O6 at 1 atm . In: Journal of the Faculty of Science, Hokkaido University. Series 4, Geology and mineralogy . tape 18 , no. 3 , 1978, p. 409-432 ( eprints.lib.hokudai.ac.jp [PDF; 3.9 MB ; accessed on December 1, 2018]).
  15. ↑ Masato Okui, Yumiko Kamimura, Shinya Hatano, Masaya Ohta and Fumiyuki Marumo: Synthesis of Non-stoichiometric Clinopyroxenes in the System Diopside-Esseneite under Ambient Pressure . In: 日本 大学 文理 学部 自然科学 研究所 研究 紀要 . tape 36 , 2001, p. 97–101 ( chs.nihon-u.ac.jp [PDF; 57 kB ; accessed on November 30, 2018]).
  16. ↑ Subrata Ghose, Fujio P. Okamura, Haruo Ohashi: The crystal structure of CaFe3 + SiAlO6 and the crystal chemistry of Fe3 + —Al3 + substitution in calcium Tschermak's pyroxene . In: Contributions to Mineralogy and Petrology . tape 92 , 1986, pp. 530-535 , doi : 10.1007 / BF00374434 .
  17. ↑ Masato Okui, Fumiyuki Marumo, Haruo Sawada, Masatoshi Ueki and Nobuo Ishizawa: Site confirmation of Fe3 + in a synthetic ferrian aluminian diopside with an application of X-ray anomalous dispersion . In: Mineralogical Journal . tape 19 , no. 4 , 1997, p. 165–172 ( jstage.jst.go.jp [PDF; 762 kB ; accessed on December 2, 2018]).
  18. ↑ Haruo Ohashi, Yu Hariya: Phase relation of CaFeAlSiO6 proxene at high pressures and temperatures. In: J Jap Assoc Mineral Petrol Econ Geol . tape 70 , 1975, pp. 93–95 ( jstage.jst.go.jp [PDF; 83 kB ; accessed on December 3, 2018]).
  19. ^ S. Gross: The mineralogy of the Hatrurim formation, Israel. In: Geol. Surv. Isr. Bull. Band 70 , 1977, pp. 1–80 ( rruff.info [PDF; 5.7 MB ; accessed on July 29, 2018]).
  20. ↑ Justyna Ciesielczuk, Łukasz Kruszewski, Jarosław Majka: Comparative mineralogical study of thermally-altered coal-dump waste, natural rocks and the products of laboratory heating experiments . In: International Journal of Coal Geology . tape 139 , 2015, p. 114–141 ( s3.amazonaws.com [PDF; 4.8 MB ; accessed on December 4, 2018]).
  21. ↑ Find location list for Esseneit in the Mineralienatlas and in Mindat
  22. ↑ Marie-Lola Pascal, Ildiko Katona, Michel Fonteilles, Jean Verkaeren: Relics of high-temperature clinopyroxene on the join Di-CaTs with up to 72 mol.% Ca (Al, Fe3 +) AlSiO6 in the skarns of Ciclova and Magureaua Vatei, Carpathians, Romania . In: The Canadian Mineralogist . tape 43 , no. 3 , June 2005, ISSN  0008-4476 , p. 857-881 , doi : 10.2113 / gscanmin.43.3.857 ( rruff.info [PDF; 1.6 MB ; accessed on December 28, 2018]).
  23. ↑ Francesco Stoppa, Victor V. Sharygin: Melilitolite intrusion and pelite digestion by high temperature kamafugitic magma at Colle Fabbri, Spoleto, Italy . In: Lithos . tape 112 , 2009, p. 306-320 ( researchgate.net [PDF; 1.8 MB ; accessed on December 7, 2018]).
  24. ↑ MC Ferro, Christian Leroy, Regina da Conceição, Corredeira Monteiro, Maria Helena, FV Fernandes: Fine-Grained Glass-Ceramics Obtained by Crystallization of Vitrified Coal Ashes . In: Key Engineering Materials . tape 230–232 , 2002, pp. 408-411 , doi : 10.4028 / www.scientific.net / KEM.230-232.408 .
  25. ↑ E. Bernardo, L. Esposito, E. Rambaldi, A. Tucci, Y. Pontikes, GN Angelopoulos: Sintered esseneite-wollastonite-plagioclase glass-ceramics from vitrified waste . In: Journal of the European Ceramic Society . tape 29 , no. 14 , 2009, p. 2921-2927 , doi : 10.1016 / j.jeurceramsoc.2009.05.017 .