Milotaite

Milotaite
General and classification
other names	IMA 2003-056
chemical formula	PdSbSe
Mineral class; (and possibly department)	Sulfides and sulfosalts
System no. to Strunz ; and to Dana	2.EB.25 ; 02.12.03.15
Crystallographic Data
Crystal system	cubic
Crystal class ; symbol	tetrahedral-pentagon-dodecahedral; 23
Space group	P 2 1 3 (No. 198)
Lattice parameters	a = 6.3181 Å
Formula units	Z = 4
Physical Properties
Mohs hardness	4.5 ( VHN 100 = 420 to 514, average 465 kg / mm 2 )
Density (g / cm 3 )	calculated: 8.09
Cleavage	no
Break ; Tenacity	uneven; brittle
colour	silver-gray, white in incident light
Line color	Gray
transparency	opaque (opaque)
shine	Metallic luster

Milotaite is a very seldom occurring mineral from the mineral class of " sulfides and sulfosalts " with the chemical composition PdSbSe and thus chemically a palladium - antimony - selenide . As close relatives of the sulfides, the selenides are placed in the same class.

Milotaite crystallizes in the cubic crystal system , but has so far only been found in the form of tiny, irregular grains up to about 25 μm in size. The mineral is in any form opaque ( opaque ) and displays on the surfaces of silver-gray in reflected light and white, grains have a metallic luster . Its line color is also gray.

Etymology and history

The compound PdSbSe could already be synthesized in 2001 by Aloys J. Foecker and Wolfgang Jeitschko. The crystal structure could also be determined from the synthesis .

Natural mineral formation Milotait was first in a uranium ore - deposit near to Kovářov belonging district Předbořice about 6 km south of Krasna Hora nad Vltavou (formerly Schoenberg ) in the Czech písek district discovered. The mineral was analyzed and described by Werner H. Paar, Dan Topa, Emil Makovicky and Franz J. Culetto, who named it after the mineralogist Milota Makovicky (* 1941) from the University of Copenhagen in recognition of their outstanding achievements in the research of sulphide and sulfarsenide systems with elements of the platinum group.

The test results and the chosen name for the newly discovered mineral were submitted to the International Mineralogical Association for examination in 2003 (internal submission number of the IMA: 2003-056), which recognized the milotaite as an independent mineral type. The first description was published two years later in the specialist magazine The Canadian Mineralogist .

The type material of the mineral is stored in the department "Mineralogy and Material Sciences" of the Institute for Geography, Geology and Mineralogy in the Mineralogical Museum in Salzburg , Austria under the catalog no. 14935 kept.

classification

Since the Milotaite was only recognized as an independent mineral in 2003 and this was only published in 2005, it is not yet listed in the outdated 8th edition of the mineral classification according to Strunz . 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.18-45 . In the “Lapis system” this corresponds to the class of “sulfides and sulfosalts” and there the section “Sulfides with [the molar ratio] metal: S, Se, Te <1: 1”, where milotaite together with cobaltite , gersdorffite , hollingworthite , Irarsit , Jolliffeit , Kalungait , Platarsit , Tolovkit , Ullmannit and Willyamit form the "cobaltite group" (status 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 milotaite in the category of “metal sulfides with 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 , cobaltite, Gersdorffit-P2 ₁ 3 , Gersdorffit-Pa 3 , Gersdorffit-Pca2 ₁ , Hollingworthit, Irarsit, Jolliffeit, Kalungait, Krutovit , Maslovit , Mayingit , Michenerit , Padmait , Platarsit, Testibiopalladit , Tolovkit, 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 the milotaite to the class of "sulfides and sulfosalts" and there to the "sulfide minerals" category. Here 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 milotaite (PdSbSe), the mineral consists of palladium (Pd), antimony (Sb) and selenium (Se) in a molar ratio of 1: 1: 1. This corresponds to a mass fraction calculated from the atomic weight of the elements ( Weight%) of 34.65% Pd, 39.64% Sb and 25.71% Se. Since antimony and selenium behave like sulfur- like non - metals in the compound , they are added together and the molar ratio is given as metal: sulfur (selenium, tellurium) = 1: 2.

Five electron beam microanalyses on two grains of the type material, however, showed a slightly different composition averaging 34.17% by weight Pd, 38.03% by weight Sb and 26.38% by weight Se, as well as minor foreign additions of 0.78% by weight % Copper (Cu) and 0.35% by weight silver (Ag), which corresponds to the empirical formula Pd _0.98 Cu _0.04 Ag _0.01 Sb _0.95 Se _1.02 .

The results of 17 analyzes on 4 grains of the synthetic analogue of milotaite also deviate slightly from the idealized composition with 34.46% by weight of Pd, 38.86% by weight of Sb and 26.60% by weight of Se.

Crystal structure

Milotaite crystallizes cubically in the space group P 2 ₁ 3 (space group no. 198) . The lattice parameter of a = 6.3181 Å was determined for synthetic milotaite. The unit cell contains four formula units . Template: room group / 198

Education and Locations

Milotaite formed in a selenium-rich, low-temperature uranium mineralization and has so far only been observed in a polished section of a hypidiomorphic mineral grain of around 25 μm. Milotaite was found there embedded in eukairite and tiemannite and grown together with bornite and digenite . More Begleitminerale are Chrisstanleyit , Fischesserit , native gold , silver rich Hakit , Tyrrellit , Clausthalit , Chaméanit and uraninite . As gait still occurs calcite added.

The only known location for milotaite is its type locality Předbořice near Kovářov in Okres Písek (Central Bohemia) in the Czech Republic . Besides Milotait also Fischesserit were here Hakit- (Hg) , Permingeatit and Petříčekit first discovered.

literature

Aloys J. Foecker, Wolfgang Jeitschko: The atomic order of the pnictogen and chalcogen atoms in equiatomic ternary compounds TPnCh (T = Ni, Pd; Pn = P, As, Sb; Ch = S, Se, Te) . In: Journal of Solid State Chemistry . tape 162 , 2001, p. 69-78 , doi : 10.1006 / jssc.2001.9342 (English).
Werner H. Paar, Dan Topa, Emil Makovicky, Franz J. Culetto: Milotaite, PdSbSe, a new palladium mineral species from Předbořice, Czech Republic . In: The Canadian Mineralogist . tape 43 , 2005, p. 689–694 (English, rruff.info [PDF; 199 kB ; accessed on July 4, 2020]).
Paula C. Piilonen, Andrew Locock, Edward S. Grew: New mineral names . In: American Mineralogist . tape 90 , 2005, pp. 1945–1952 (English, rruff.info [PDF; 241 kB ; accessed on July 4, 2020]).
Milotaite . 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; 82 kB ; accessed on July 4, 2020]).

Web links

Milotaite. In: Mineralienatlas Lexikon. Stefan Schorn u. a., accessed on July 4, 2020 .
Milotaite. In: mindat.org. Hudson Institute of Mineralogy, accessed July 4, 2020 .
David Barthelmy: Milotaite Mineral Data. In: webmineral.com. Retrieved July 4, 2020 .
American-Mineralogist-Crystal-Structure-Database - Milotaite. In: rruff.geo.arizona.edu. Retrieved July 4, 2020 .

Individual evidence

↑ ^a ^b ^c ^d Malcolm Back, William D. Birch, Michel Blondieau and others: The New IMA List of Minerals - A Work in Progress - Updated: July 2020. (PDF; 2.44 MB) In: cnmnc.main.jp . IMA / CNMNC, Marco Pasero, July 2020, accessed July 4, 2020 .
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o Werner H. Paar, Dan Topa, Emil Makovicky, Franz J. Culetto: Milotaite, PdSbSe, a new palladium mineral species from Předbořice, Czech Republic . In: The Canadian Mineralogist . tape 43 , 2005, p. 689–694 (English, rruff.info [PDF; 199 kB ; accessed on July 4, 2020]).
↑ Aloys J. Föcker, Wolfgang Jeitschko: The atomic order of the pnictogen and chalcogen atom in equiatomic ternary compounds TPnCh (T = Ni, Pd; Pn = P, As, Sb, Ch = S, Se, Te) . In: Journal of Solid State Chemistry . tape 162 , 2001, p. 69-78 , doi : 10.1006 / jssc.2001.9342 (English).
↑ Stefan Weiß: The large 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 .
↑ 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 July 4, 2020 .
↑ Milotaite. In: Mineralienatlas Lexikon. Stefan Schorn u. a., accessed on July 4, 2020 .
↑ List of locations for milotaite in the Mineralienatlas and Mindat , accessed on July 4, 2020.
↑ Type locality Předbořice, Kovářov, Okres Písek, Böhmen, Czech Republic from the Mineralienatlas and from Mindat , accessed on July 4, 2020.

[IMA-Liste-2020-07-1] Malcolm Back, William D. Birch, Michel Blondieau and others: The New IMA List of Minerals - A Work in Progress - Updated: July 2020. (PDF; 2.44 MB) In: cnmnc.main.jp . IMA / CNMNC, Marco Pasero, July 2020, accessed July 4, 2020 .

[PaarTopaMakovickyCuletto-2] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o Werner H. Paar, Dan Topa, Emil Makovicky, Franz J. Culetto: Milotaite, PdSbSe, a new palladium mineral species from Předbořice, Czech Republic . In: The Canadian Mineralogist . tape 43 , 2005, p. 689–694 (English, rruff.info [PDF; 199 kB ; accessed on July 4, 2020]).

[FoeckerJeitschko-3] Aloys J. Föcker, Wolfgang Jeitschko: The atomic order of the pnictogen and chalcogen atom in equiatomic ternary compounds TPnCh (T = Ni, Pd; Pn = P, As, Sb, Ch = S, Se, Te) . In: Journal of Solid State Chemistry . tape 162 , 2001, p. 69-78 , doi : 10.1006 / jssc.2001.9342 (English).

[Lapis-4] Stefan Weiß: The large 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 .

[IMA-Liste-2009-5] 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 July 4, 2020 .

[MA-6] Milotaite. In: Mineralienatlas Lexikon. Stefan Schorn u. a., accessed on July 4, 2020 .

[Fundorte-7] List of locations for milotaite in the Mineralienatlas and Mindat , accessed on July 4, 2020.

[Predborice-8] Type locality Předbořice, Kovářov, Okres Písek, Böhmen, Czech Republic from the Mineralienatlas and from Mindat , accessed on July 4, 2020.