Iyoit

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Iyoit
General and classification
other names

IMA 2013-130

chemical formula
  • MnCuCl (OH) 3
  • CuMn (OH 3 ) Cl
Mineral class
(and possibly department) 		Halides
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Space group P 2 1 / m (No. 11)Template: room group / 11
Lattice parameters a  = 5.7208 (8)  Å ; b  = 6.6045 (7) Å; c  = 5.6224 (7) Å α  = 88.363 (4) °; 
Formula units Z  = 2
Frequent crystal faces {001}, {100}, {010}, {110}
Physical Properties
Mohs hardness 3
Density (g / cm 3 ) calculated: 3.22
Cleavage not defined
Break ; Tenacity uneven; brittle
colour light green, yellowish green
Line color pale green
transparency transparent
shine Glass gloss
Crystal optics
Refractive indices n α  = 1.698 (2)
n β  = 1.725 (3)
n γ  = 1.737 (3)
Optical character biaxial negative
Axis angle 2V = 66 (2) ° (measured); 66.5 ° (calculated)
Pleochroism X = light bluish green, Y ≈ Z = bluish green

Iyoit is a very rarely occurring mineral from the mineral class of " halides " with the chemical composition CuMn (OH 3 ) Cl or MnCuCl (OH) 3 and thus, chemically speaking, a copper - manganese oxyhalide.

Iyoite crystallizes in the monoclinic crystal system , but has so far only been discovered in the form of microscopic crystals with a leafy habit up to about 200 μm , which predominantly come together to form radial or dendritic mineral aggregates . The crystals are transparent, light green to yellowish green in color and have a glass-like sheen on the surface .

Etymology and history

Was first discovered Iyoit with Misakiit in the copper deposit of Ohku mine on the main Japanese island of Shikoku belonging Peninsula Sadamisaki . The first description was published in 2017 by Daisuke Nishio-Hamane, Koichi Momma, M. Ohnishi, Norimasa Shimobayashi, R. Miyawaki, N. Tomita, R. Okuma, AR Kampf and T. Minakawa, who named the mineral after the Iyo Sea ( English: Sea of ​​Iyo ) off the coast of Sadamisaki.

The type material of the mineral is in the National Museum of Natural Sciences in Tokyo (Japan) under catalog no. M43864 and in the Mineralogical Department of the Natural History Museum of Los Angeles County in Los Angeles (California, USA) under catalog no. 66625 kept.

classification

Iyoit was only recognized as an independent mineral by the International Mineralogical Association (IMA) in 2013 and this was published in 2014. An exact group assignment in the 9th edition of the Strunz'schen mineral systematics , the last update of which was carried out with the publication of the IMA list of mineral names in 2009, is therefore not yet known. In the first description by Nishio-Hamane et al. However, Iyoit and Misakiit are declared as new members of the Atacamite group. Accordingly, it can be assumed that the two minerals are classified in the section “ Oxihalides, Hydroxyhalides and Related Double Halides ” and there in the sub-section “With Cu etc., without Pb”, where the atacamite group with system no. 3.DA.10a currently consists of the members Atacamit , Hibbingit and Kempit .

In the "Lapis Mineralienverzeichnis", which was last published in March 2018, which, out of consideration for private collectors and institutional collections, is still based on the classical systematics of Karl Hugo Strunz in the 8th edition , Iyoit received the system and mineral no. III / D.01-50 , which corresponds to the "Lapis Classification" the department "oxyhalides" where the mineral along with Anthonyit , Atacamit, Belloit , Bobkingit , Botallackit , Calumetit , Gillardit , Haydeeit , Herbertsmithite , Hibbingit, Kapellasit , Kempit, Klinoatacamit , Korshunovskit , Leverettit , Melanothallit , Misakiit, Nepskoeit , Paratacamit , Paratacamit- (Mg) , Paratacamit- (Ni) , Tondiit forms a separate, but unnamed group.

Chemism

Seven microprobe analyzes on Iyoite samples from the type locality showed an average composition of 37.78% by weight of manganese (II) oxide (MnO), 35.74% by weight of copper (II) oxide (CuO), 18.42% by weight % Chlorine (Cl) and 13.01% by weight H 2 O (calculated on the basis of the stoichiometry , O = Cl −4.16). On the basis of 4 anions per formula unit (pfu), the empirical formula Mn 1.085 Cu 0.915 Cl 1.058 (OH) 2.942 was calculated and idealized to MnCuCl (OH) 3 .

Crystal structure

Iyoit crystallizes monoclinically in the space group P 2 1 / m (space group no. 11) with the lattice parameters a  = 5.7208 (8)  Å ; b  = 6.6045 (7) Å; c  = 5.6224 (7) Å and β = 88.363 (4) ° as well as two formula units per unit cell . Template: room group / 11

Education and Locations

Iyoit formed secondarily by the reaction between sea water and the primary ore minerals as Alleghanyite , chalcocite , hausmannite , solid copper , rhodochrosite , Rhodonit and Tephroit in greenschists facies from metamorphosed volcanic sulfide - deposits . As Begleitminerale occur next Misakiit among other chrysocolla , cuprite , Kutnohorit and Malachite on.

Apart from its type locality , the Ohku Mine copper deposit on the Sadamisaki Peninsula , no other sites for Iyoit are known to date (as of 2019).

See also

literature

  • PA Williams, F. Hatert, M. Pasero, SJ Mills: IMA Commission on new minerals, nomenclature and classification (CNMNC) Newsletter 20. New minerals and nomenclature modifications approved in 2014 . In: Mineralogical Magazine . tape 78 , 2014, p. 549–558 (English, available online at rruff.info [PDF; 106 kB ; accessed on March 3, 2019]).
  • Dmitriy I. Belakovskiy, Fernando Cámara, Olivier C. Gagné: New Mineral Names . In: American Mineralogist . tape 102 , 2017, p. 2341–2347 (English, available online at rruff.info [PDF; 522 kB ; accessed on March 3, 2019]).
  • D. Nishio-Hamane, Koichi Momma, M. Ohnishi, Norimasa Shimobayashi, R. Miyawaki, N. Tomita, R. Okuma, AR Kampf, T. Minakawa: Iyoite, MnCuCl (OH) 3 and misakiite, Cu 3 Mn (OH ) 6 Cl 2 : New members of the atacamite family from Sadamisaki Peninsula, Ehime Prefecture, Japan . In: Mineralogical Magazine . tape 81 , 2017, p. 485–498 , doi : 10.1180 / minmag.2016.080.104 (English, accessed via De Gruyter Online).

Web links

Individual evidence

  1. ↑ a b c Malcolm Back, William D. Birch, Michel Blondieau and others: The New IMA List of Minerals - A Work in Progress - Updated: November 2018. (PDF 1753 kB) In: cnmnc.main.jp. IMA / CNMNC, Marco Pasero, November 2018, accessed March 3, 2019 .
  2. ↑ a b c d e f Stefan Weiss: The great Lapis mineral directory. All minerals from A - Z and their properties. Status 03/2018 . 7th, completely revised and supplemented edition. Weise, Munich 2018, ISBN 978-3-921656-83-9 .
  3. ↑ a b c d Iyoite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 (English, handbookofmineralogy.org [PDF; 350  kB ; accessed on March 3, 2019]).
  4. ↑ a b c D. Nishio-Hamane, Koichi Momma, M. Ohnishi, Norimasa Shimobayashi, R. Miyawaki, N. Tomita, R. Okuma, AR Kampf, T. Minakawa: Iyoite, MnCuCl (OH) 3 and misakiite, Cu 3 Mn (OH) 6 Cl 2 : New members of the atacamite family from Sadamisaki Peninsula, Ehime Prefecture, Japan . In: Mineralogical Magazine . tape 81 , 2017, p. 490 , doi : 10.1180 / minmag.2016.080.104 (English, accessed via De Gruyter Online).
  5. ↑ a b c d e f g D. Nishio-Hamane, Koichi Momma, M. Ohnishi, Norimasa Shimobayashi, R. Miyawaki, N. Tomita, R. Okuma, AR Kampf, T. Minakawa: Iyoite, MnCuCl (OH) 3 and misakiite, Cu 3 Mn (OH) 6 Cl 2 : New members of the atacamite family from Sadamisaki Peninsula, Ehime Prefecture, Japan . In: Mineralogical Magazine . tape 81 , 2017, p. 487–488 , doi : 10.1180 / minmag.2016.080.104 (English, accessed via De Gruyter Online).
  6. ↑ D. Nishio-Hamane, Koichi Momma, M. Ohnishi, Norimasa Shimobayashi, R. Miyawaki, N. Tomita, R. Okuma, AR Kampf, T. Minakawa: Iyoite, MnCuCl (OH) 3 and misakiite, Cu 3 Mn ( OH) 6 Cl 2 : New members of the atacamite family from Sadamisaki Peninsula, Ehime Prefecture, Japan . In: Mineralogical Magazine . tape 81 , 2017, p. 490 , doi : 10.1180 / minmag.2016.080.104 (English, accessed via De Gruyter Online).
  7. ↑ IMA / CNMNC List of Mineral Names September 2009 (PDF 1.8 MB with the last official Strunz classification)
  8. ↑ Find location list for Iyoit at the Mineralienatlas and at Mindat