Falkmanite

Falkmanite
	Falkmanite from the Bayerland mine, Pfaffenreuth ( municipality of Leonberg ), Upper Palatinate Forest, Bavaria (size: 8.5 cm × 3.4 cm × 2.5 cm)
General and classification
other names	Lead luster ore
chemical formula	Pb 3 Sb 2 S 6
Mineral class; (and possibly department)	Sulfides and sulfosalts
System no. to Strunz ; and to Dana	2.HC.15 ( 8th edition : II / E.19) ; 05/03/02/02
Similar minerals	Boulangerite
Crystallographic Data
Crystal system	monoclinic
Crystal class ; symbol	monoclinic prismatic; 2 / m
Space group	P 2 1 / a (No. 14, position 3)
Lattice parameters	a = 21.55 Å ; b = 23.48 Å; c = 8.09 Å ; β = 100.7 °
Formula units	Z = 8
Physical Properties
Mohs hardness	2.5
Density (g / cm 3 )	6.24
Cleavage	Please complete
colour	lead gray to gray black
Line color	black
transparency	opaque
shine	Metallic luster

Falkmanite is a rarely occurring mineral from the mineral class of "sulfides and sulfosalts" with the chemical composition Pb ₃ Sb ₂ S ₆ , so it consists of lead , antimony and sulfur in a molar ratio of 3: 2: 6. Structurally, the mineral belongs to the sulfosalts .

Falkmanite is opaque in every form, crystallizes in the monoclinic crystal system and is mostly found in the form of tufted to radiant mineral aggregates , but also develops needle-like to tabular crystals from lead-gray to gray-black in color. Its line color , on the other hand, is black throughout.

Etymology and history

Falkmanite was first discovered in the Bayerland mine near Waldsassen in the Upper Palatinate district of Tirschenreuth and described in 1940 by Paul Ramdohr and Olof Ödmann. They named the mineral after Oscar Falkman (actually Oscar Carl August Falkman , 1877–1961), the Swedish industrialist and former director of the Boliden mining company .

classification

Already in the now outdated, but still in use 8th edition of the mineral classification according to Strunz , the Falkmanite belonged to the mineral class of "sulfides and sulfosalts" and there to the department of "sulfosalts (S: As, Sb, Bi = x)", where it belongs together with Ardait , Boulangerit , Jaskólskiit , Moëloit and Pillait formed the unnamed group II / E.19 .

The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the IMA, classifies the Falkmanite in the newly defined section of "Sulphosalts with SnS as a model". This is further subdivided according to the predominant metals in the compound, so that the mineral can be found according to its composition in the sub-section "Only with lead (Pb)", where it is only together with boulangerite and plumosite the "boulangerite group" with the system -No. 2.HC.15 forms.

The systematics of minerals according to Dana also assigns the Falkmanite to the class of "sulfides and sulfosalts" and there in the department of "sulfosalts". Here it is together with Boulangerite in the unnamed group 05/03/02 within the subdivision of “ Sulphosalts with the ratio 2.5 <z / y <3 and the composition (A ⁺ ) _i (A ²⁺ ) _j [B _y C _z ], where A = metals, B = semimetals, C = non-metals ”.

Crystal structure

Falkmanite crystallizes monoclinically in the space group P 2 ₁ / a (space group no. 14, position 3) with the lattice parameters a = 21.55 Å ; b = 23.48 Å; c = 8.09 Å and β = 100.7 ° and 8 formula units per unit cell . Template: room group / 14.3

properties

Falkmanite is reflective pleochroitic , that is, its color is pure white in the air, but bluish to greenish white in oil.

Education and Locations

Falkmanit formed hydrothermally in quartz - courses where he primarily in intimate paragenesis with Geokronit occurs. Other accompanying minerals include arsenopyrite , bournonite , chalcopyrite , galena , jarnesonite , pyrite , pyrrhotite , tetrahedral and vallerite .

As a rare mineral formation, Falkmanite could only be detected at a few sites, whereby so far (as of 2016) a little more than 10 sites are known. In addition to its type locality Grube Bayerland in Upper Palatinate , the mineral was only found in Germany in the case of fire wood (municipality of Goldkronach ) in the Fichtel Mountains (Bavaria).

The only place of discovery in Sweden so far is the Boliden pit in the administrative province of Västerbotten County (previously Västerbotten ) , which was already described by Ramdohr and Ödmann .

Other previously known sites are the

Pinnacles Mine at Broken Hill, New South Wales and the Woodcutters Mine at Batchelor (Northern Territory) in Australia
Tornohuaico Mine near Porco in the Potosí Department in Bolivia
Polymetallic deposits "Bairendaba" and "Bianjiadayuan" in the Hexigte -Banner administrative district of the Inner Mongolia Autonomous Region in China
Plaka Mine No. 80 (Filoni 80) in the Lavrio district ( Attica region ) in Greece
Trepča Stan Terg Mine in the Trepča complex northeast of Mitrovica in Kosovo
Deposits and ore fields near Crveni Breg on Mount Avala (Belgrade) and Boranja (Podrinje) in Serbia
Area around Hnúšťa and Zlatá Baňa in Slovakia

literature

Paul Ramdohr , Olof Ödman: Falkmanite, a new lead luster ore and its occurrence, especially in Boliden and the Bayerland mine. (With a contribution to the knowledge of geocronite.) In: New Yearbook for Mineralogy Beilagen-Volume A 75 (1939), pp. 315-350

New Mineral Names. Falkmanite In: American Mineralogist Volume 25 (4), 1940, pp. 312–314 ( PDF 196 kB )

SC Robinson: The identity of Falkmanite and Yenerite with Boulangerite In: American Mineralogist Volume 33 (11 + 12), 1948 ( PDF 555.2 kB )

Hans Jürgen Rösler : Textbook of Mineralogy . 4th revised and expanded edition. German publishing house for basic industry (VEB), Leipzig 1987, ISBN 3-342-00288-3 , p. 350 .

Kenneth G. McQueen: A second occurrence of Falkmanite: Pinnacles Mine, Broken Hill, New South Wales In: Canadian Mineralogist Volume 25, 1987, pp. 15-19 ( PDF 702 kB )

Web links

Commons : Falkmanite - collection of images, videos and audio files

Individual evidence

↑ ^a ^b IMA / CNMNC List of Mineral Names; November 2015 (PDF 1.5 MB)
^ ^A ^b 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 , p. 134 .
↑ ^a ^b Paul Ramdohr , Olof Ödmann : Falkmanite, a new lead luster ore and its occurrence, especially in Boliden and mine Bayerland In: Chemisches Zentralblatt , No. 17, 1st half of 1940, p. 2620 ( PDF 13.2 MB ; p. 20)
↑ ^a ^b ^c New Mineral Names. Falkmanite In: American Mineralogist Volume 25 (4), 1940, pp. 312–314 ( PDF 196 kB )
^ Mindat - Falkmanite
↑ Find location list for Falkmanite in the Mineralienatlas and Mindat

[IMA-Liste-2015-11-1] IMA / CNMNC List of Mineral Names; November 2015 (PDF 1.5 MB)

[StrunzNickel-2] A ^b 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 , p. 134 .

[RamdohrÖdmann-3] Paul Ramdohr , Olof Ödmann : Falkmanite, a new lead luster ore and its occurrence, especially in Boliden and mine Bayerland In: Chemisches Zentralblatt , No. 17, 1st half of 1940, p. 2620 ( PDF 13.2 MB ; p. 20)

[AM25-4-1940-4] New Mineral Names. Falkmanite In: American Mineralogist Volume 25 (4), 1940, pp. 312–314 ( PDF 196 kB )

[MindatAnzahl-5] Mindat - Falkmanite

[Fundorte-6] Find location list for Falkmanite in the Mineralienatlas and Mindat