Tolovkit

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Tolovkit
General and classification
other names

IMA 1980-055

chemical formula IrSbS
Mineral class
(and possibly department) 		Sulfides and sulfosalts
System no. to Strunz
and to Dana 		2.EB.25
02.12.03.05
Crystallographic Data
Crystal system cubic
Crystal class ; symbol tetrahedral-pentagon-dodecahedral; 23
Space group P 2 1 3 (No. 198)Template: room group / 198
Lattice parameters a  = 6.03  Å
Physical Properties
Mohs hardness 7.5 to 8 ( VHN 10  = 1522 (1431–1703))
Density (g / cm 3 ) calculated: 10.50
Cleavage is missing
Break ; Tenacity clamshell; brittle
colour steel gray, in incident light gray with a light brown tinge
Line color black
transparency opaque
shine Metallic luster

Tolovkite is a very rarely occurring mineral from the mineral class of " sulfides and sulfosalts " with the idealized chemical composition IrSbS and thus chemically an iridium - antimony sulfide.

Tolovkite crystallizes in the cubic crystal system , but has so far only been found in the form of tiny, isometric and irregular grains and aggregates up to about 72  μm in size. The mineral is in any form opaque ( opaque a metal) and shows not corroded on the surfaces of grains gloss . In contrast to the steel-gray surface color , which also appears gray with a light brown tinge in incident light, the line color of Tolovkit is black.

Etymology and history

Tolovkit was first discovered in a soap deposit on the Tolovka river of the same name on the Ultrabasit massif Ust'-Bel'skii in the Koryak Mountains on the Kamchatka Peninsula in Russia's Far East. The first description was published in 1981 by LV Razin, NS Rudashevsky and GA Sidorenko (Russian Л. В. Разин, Н. С. Рудашевский, Г. А. Сидоренко ) after recognition by the International Mineralogical Association (internal entry number of the IMA : 1980-055). Razin and his team named the mineral after its type locality .

The type material of the mineral is stored in the Mining Institute of Saint Petersburg and in the Fersman Museum (catalog number 72030 ) of the Russian Academy of Sciences in Moscow (Russia).

classification

Since the Tolovkite was only recognized as an independent mineral in 1980, it is not yet listed in the 8th edition of the mineral classification according to Strunz , which has been outdated since 1977 . Only in the Lapis mineral directory according to Stefan Weiß, which, out of consideration for private collectors and institutional collections, is still based on this old form of Karl Hugo Strunz's system , was the mineral given the system and mineral number. II / D.18-80 . In the "Lapis Classification" This also corresponds to the department "sulfides with [molar ratio] Metal: S, Se, Te <1: 1" where Tolovkit with Cobaltit , Gersdorffit , Hollingworthit , Irarsit , Jolliffeit , Kalungait , Milotait , Platarsite , ullmannite and willyamite form the "cobaltite group" (II / D.18) (as of 2018).

The 9th edition of Strunz's mineral systematics, which has been in effect since 2001 and was updated by the IMA until 2009, classifies the Tolovkite in the newly defined section of "Metal sulfides with a molar ratio of M: S ≤ 1: 2". This is further subdivided according to the exact molar ratio and the predominant metals in the compound, so that the mineral can be found in the sub-section "M: S = 1: 2, with Fe, Co, Ni, PGE etc." according to its composition where it together with Changchengit, Cobaltit, Gersdorffit-P213 , Gersdorffit-Pa3 , Gersdorffit-Pca21 , Hollingworthit, Irarsit, Jolliffeit, Kalungait, Krutovit , Maslovit, Mayingit , Michenerit, Milotait, Padmait, Platarsit, Testibiopalladit, Ullmannit and Willyamit the " Gersdorffitgruppe "with the system no. 2.EB.25 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns tolovkite to the class of "sulfides and sulfosalts" and there in the department of "sulfide minerals". Here, however, it is in the " cobaltite group (cubic or pseudocubic crystals) " with the system no. 02.12.03 within the subsection "Sulphides - including selenides and tellurides - with the composition A m B n X p , with (m + n): p = 1: 2".

Chemism

According to the idealized (theoretical) composition of Tolovkit (IrSbS), the mineral consists of iridium (Ir), antimony (Sb) and sulfur (S) in a molar ratio of 1: 1: 1, which corresponds to a mass fraction (% by weight) of 55, Corresponds to 55% Ir, 35.19% Sb and 9.27% ​​S.

Microprobe analyzes on the type material from Kamchatka showed slightly different proportions of Ir of 55.00 and 56.6% by weight, Sb of 34.7 and 35.00% by weight and S of 9.20 and 9.22% by weight. -%. In addition, admixtures of 0.25 or 0.69% by weight of platinum (Pt), 0.12 or 0.49% by weight of osmium (Os) and 0.06% by weight of nickel (Ni) were measured . The measurement results correspond to the empirical formula (Ir 0.993 Pt 0.009 Os 0.006 ) Σ1.014 Sb 0.993 S 0.993 , which has been idealized as the pure formula IrSbS.

Crystal structure

Tolovkite crystallizes cubically in the space group P 2 1 3 (space group no. 198) with the lattice parameter a  = 6.03  Å and four formula units per unit cell . Template: room group / 198

Education and Locations

At its type locality on the Tolovka River , the mineral was found in the form of adhesions in Os-Ir alloys in soap deposits that were formed in the Quaternary . Laurite , pentlandite and Heazlewoodite appeared as additional accompanying minerals .

Tolovkite is one of the very rare mineral formations that has so far only been known in a few mineral samples. Depending on the sources, between 9 and 15 sites have been documented worldwide. In addition to its type locality Tolovka on Kamchatka, the mineral was also found in Russia on the Fadeevka River, also in the Far East, near Lake Khanka in the Primorye region, on the Bolshoy Khailyk River in the Krasnoyarsk region in Siberia and in the Kialim soap deposit on the Miass River in the Chelyabinsk Oblast, in the Uktus Complex near Yekaterinburg in Sverdlovsk Oblast and the Centralnoye II Ir-Rh-Ni sulphide deposit near Rai-Iz (Raiz) in Tyumen Oblast in the Urals.

Within Europe Tolovkit entered so far only in the chromite -Lagerstätte Østhammeren with PGE -Mineralisation at Røros in Trøndelag Fylke in Norway and in the quarry Harold's Grave on the Scottish island of Unst in the UK.

Tolovkit was also able to work in soap deposits on the Tulameen River and the Similkameen River in the Canadian province of British Columbia, in the ultramafites of the Sikhuran mine near Esfandagheh near Jiroft in the Iranian province of Kerman, on the Panke Horonai River near Ashibetsu on the Japanese island of Hokkaidō as well found in the platinum soap Fox Gulch on the Salmon River ( Bethel Census Area ) in Alaska and near Annapolis in Iron County of Missouri in the United States of America.

See also

literature

  • Л. В. Разин, Н. С. Рудашевский, Г. А. Сидоренко: Толовкит IrSbS - новый Сульфоантимонид Иридия с Северо-Востока СССР . In: Zapiski Vsesoyuznogo Mineralogicheskogo Obshchestva . tape 110 , no. 4 , 1981, p. 474–480 (Russian, rruff.info [PDF; 756 kB ; accessed June 24, 2020] English translation: LV Razin, NS Rudashevsky, GA Sidorenko: Tolovkite, IrSbS, a new sulfoantimonide of iridium from northeastern USSR ).
  • Michael Fleischer , Louis J. Cabri, GY Chao, JA Mandarino , Adolf Pabst : New mineral names . In: American Mineralogist . tape 67 , 1982, pp. 1074-1082 (English, rruff.info [PDF; 857 kB ; accessed on June 24, 2020]).
  • Peter Bayliss: Crystal chemistry and crystallography of some minerals within the pyrite group . In: American Mineralogist . tape 74 , 1989, pp. 1168–1176 (English, rruff.info [PDF; 1,2 MB ; accessed on June 24, 2020]).

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: March 2020. (PDF; 2.44 MB) In: cnmnc.main.jp. IMA / CNMNC, Marco Pasero, March 2020, accessed June 23, 2020 .
  2. ^ A b c Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables. Chemical-structural Mineral Classification System . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X (English).
  3. ↑ a b c d e 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 .
  4. ↑ a b c Michael Fleischer , Louis J. Cabri, GY Chao, JA Mandarino , Adolf Pabst : New mineral names . In: American Mineralogist . tape  67 , 1982, pp. 1074-1082 (English, rruff.info [PDF; 857 kB ; accessed on June 24, 2020]).
  5. ↑ a b c d Tolovkite . 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; 60  kB ; accessed on June 25, 2020]).
  6. ↑ Ernest H. Nickel , Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF; 1.82 MB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed June 23, 2020 .
  7. ↑ Tolovkit. In: Mineralienatlas Lexikon. Stefan Schorn u. a., accessed on June 23, 2020 .
  8. ↑ a b List of where Tolovkite was found in the Mineralienatlas and Mindat , accessed on June 25, 2020.