Wolfeit

Wolfeit
	Parallel-fiber aggregate of reddish brown Wolfeit from the Big Fish River, Dawson (Yukon) , Canada (size: 6.1 cm × 3.2 cm × 2.3 cm)
General and classification
chemical formula	Fe 2+ 2 [OH \| PO 4 ]
Mineral class; (and possibly department)	Phosphates, arsenates and vanadates
System no. to Strunz ; and to Dana	8.BB.15 ( 8th edition : VII / B.03) ; 06/41/03/01
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 = 12.32 Å ; b = 13.17 Å; c = 9.79 Å ; β = 108.0 °
Formula units	Z = 16
Physical Properties
Mohs hardness	4.5 to 5
Density (g / cm 3 )	measured: 3.79 to 3.82; calculated: 3.88
Cleavage	good after {100}, clear after {120}, indistinct after {010}, very indistinct after {110}
Break ; Tenacity	uneven to slightly scalloped; brittle
colour	pink to reddish brown, light to dark brown
Line color	White
transparency	transparent to opaque
shine	Glass gloss, silk gloss
Crystal optics
Refractive indices	n α = 1.741 to 1.750 ; n β = 1.742 to 1.750 ; n γ = 1.746 to 1.759
Birefringence	δ = 0.005 to 0.009
Optical character	biaxial positive
Axis angle	2V = 51 ° (measured)

Wolfeit is a rarely occurring minerals from the mineral class of "phosphates, arsenates, and vanadates" with the idealized chemical composition of Fe ²⁺₂ [OH | PO ₄ ] and is therefore chemically seen a iron - phosphate with additional hydroxide .

Since Wolfeit forms a complete mixed crystal row with triploidite (Mn ²⁺₂ [OH | PO ₄ ]) , a part of the manganese can be represented ( substituted ) by iron , which is indicated in various sources with the formula (Fe, Mn) ₂ [OH | PO ₄ ] is expressed.

Wolfeit crystallizes in the monoclinic crystal system and usually occurs in the form of stalky to coarsely fibrous or granular mineral aggregates up to about 10 centimeters in size, which are opaque and have a silk-like sheen on the surface. Very rarely does it develop tiny, transparent crystals with glass-glossy surfaces. Depending on the mixing ratio of iron and manganese or foreign admixtures of other elements , Wolfeit is pink to reddish brown or light to dark brown (also clove brown ) in color. The line color of the mineral, on the other hand, is always white.

Etymology and history

Wolfeit was first discovered in the “Palermo No. 1 Mine ”near Groton , Grafton County, New Hampshire, United States. It was first described in 1949 by Clifford Frondel , who named the mineral after the American crystallographer Professor Caleb Wroe Wolfe (1908–1980).

The type material of the mineral is stored in the Natural History Museum in London, England (catalog number 1963,230) and at Harvard University in Cambridge, Massachusetts, USA (catalog number 100868, 100870, 100871).

classification

Already in the outdated, but still in use 8th edition of the mineral classification according to Strunz , the Wolfeit belonged to the mineral class of "phosphates, arsenates and vanadates" and there to the department of "anhydrous phosphates, with foreign anions F, Cl, O, OH", where together with Zwieselit the "Zwieselit-Wolfeit-Gruppe" with the system no. VII / B.03 and the other members Magniotriplit (discredited 2004), Sarkinit , Staněkit , Triplit , Triploidit and Wagnerite .

The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), also assigns Wolfeit to the department of “phosphates etc. with additional anions; without H ₂ O “. However, this is further subdivided according to the relative size of the cations involved and the molar ratio of the additional anions to the phosphate, arsenate and vanadate complex, so that the mineral is classified in the sub-section “With only medium-sized cations; (OH etc.): RO ₄ ≤ 1: 1 “can be found, where together with Joosteit, Sarkinit, Staněkit, Triploidit and Wagnerit the“ Triploiditgruppe ”with the system no. 8.BB.15 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Wolfeit to the class of "phosphates, arsenates and vanadates" and there in the department of "anhydrous phosphates, etc., with hydroxyl or halogen". Here he is the sole namesake in the " Wolfeit Group " with the system no. 41.06.03 within the subsection "Anhydrous phosphates etc., with hydroxyl or halogen with (A) ₂ (XO ₄ ) Z _q ".

Crystal structure

Wolfeit crystallizes isotypically with Wagnerite in the monoclinic space group P 2 ₁ / a (space group no. 14, position 3) with the lattice parameters a = 12.32 Å ; b = 13.17 Å; c = 9.79 Å and β = 108.0 ° and 16 formula units per unit cell . Template: room group / 14.3

Education and Locations

Reddish brown Wolfeit crystal with laterally visible, slightly shell-like break from Palermo No. 1 mine, Groton , Grafton County , New Hampshire, USA ( total sample size : 4.7 cm × 2.7 cm × 1.8 cm)

Wolfeit forms secondarily as a hydrothermal conversion product from triphylene in granitic pegmatites , but can rarely also arise in hydrothermal veins and in phosphate-rich ore nests in slate . As Begleitminerale yet in addition triphylite among other apatite , Arrojadit , Hagendorfit , Marićit , Satterlyit , Triplite and Wicksit occur.

As a rare mineral formation, Wolfeit could only be proven at a few localities, whereby so far (as of 2015) a little more than 30 localities are known. In addition to its type locality “Palermo No. 1 Mine ”and the nearby“ Palermo No. 2 Mine "at Groton entered the mineral in New Hampshire still in the Keyes mica - quarries at Orange in Grafton County to light. Another location near Walpole in Cheshire County has not yet been confirmed. Otherwise Wolfeit could only be found in the United States in the Bull Moose Mine near Custer in the county of the same name and in the Big Chief Mine near Glendale in Pennington County in South Dakota.

In Germany, Wolfeit has so far only been found in Bavaria , more precisely at Hennenkobel (also Hühnerkobel ) near Rabenstein (Lower Bavaria), at the Kreuzberg natural monument and at Trutzhofmühle in the municipality of Pleystein and in the northern and southern pegmatites near Hagendorf in the municipality of Waidhaus (Upper Palatinate).

Other previously known sites in Europe include Chanteloube in the French department of Haute-Vienne (Limousin); Olgiasca-Malpensata (Piona) near Colico in the Italian province of Lecco (Lombardy); Michałkowa (Michelsdorf) on the mountain and in the Sudetes in Poland; Panasqueira near Covilhã in the Portuguese district of Castelo Branco ; Sollefteå (Ångermanland), Bräcke (Jämtland), Godegård ( Östergötland ), several sites in Södermanland and Norrskogen ( Uppland ) in Sweden; Garcirrey in the municipality of Castile and León and Cadaqués in Catalonia in Spain as well as Otov in Bohemia and Velké Meziříčí in Moravia in the Czech Republic.

Otherwise Wolfeit could only be found at a few sites in Argentina, Australia, Brazil, Canada and South Africa.

literature

Clifford Frondel : Wolfeite, xanthoxenite, and whitlockite from the Palermo Mine, New Hampshire . In: American Mineralogist . tape 34 , 1949, pp. 692–705 ( rruff.info [PDF; 933 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. 640 .
Uwe Kolitsch : Mg-rich wolfeite, (FeII, Mg) ₂ (PO ₄ ) (OH): structure refinement and Raman spectroscopic data . In: Acta Crystallographica . E59, no. 9 , September 2003, p. 125-128 , doi : 10.1107 / S1600536803017537 .
F. Hatert: Fe ^II₂ (PO ₄ ) (OH), a synthetic analogue of wolfeite . In: Acta Crystallographica . C63, 2007, p. i119-i121 , doi : 10.1107 / S0108270107053462 .

Web links

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

Individual evidence

↑ ^a ^b ^c IMA / CNMNC List of Mineral Names; November 2017 (PDF 1.67 MB; p. 204)
^ ^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 , p. 442 .
↑ ^a ^b ^c ^d ^e Wolfeite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 ( handbookofmineralogy.org [PDF; 65 kB ; accessed on March 27, 2018]).
↑ Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties . 6th completely revised and supplemented edition. Weise, Munich 2014, ISBN 978-3-921656-80-8 .
↑ ^a ^b ^c ^d ^e Mindat - Wolfeite
↑ Mindat - Number of localities for Wolfeit
↑ ^a ^b List of localities for Wolfeit in the Mineralienatlas and Mindat

[IMA-Liste-2017-11-1] IMA / CNMNC List of Mineral Names; November 2017 (PDF 1.67 MB; p. 204)

[StrunzNickel-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 , p. 442 .

[Datenblatt-3] Wolfeite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 ( handbookofmineralogy.org [PDF; 65 kB ; accessed on March 27, 2018]).

[Lapis-4] Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties . 6th completely revised and supplemented edition. Weise, Munich 2014, ISBN 978-3-921656-80-8 .

[Mindat-5] Mindat - Wolfeite

[MindatAnzahl-6] Mindat - Number of localities for Wolfeit

[Fundorte-7] List of localities for Wolfeit in the Mineralienatlas and Mindat