Miserit

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Miserit
Miserite-177631.jpg
Miserite from the Poudrette quarry, Mont Saint-Hilaire , Québec, Canada (field of view 4.4 mm × 6.1 mm)
General and classification
chemical formula KCa 5 □ [OH | F | S 2 O 7 | Si 6 O 15 ]
Mineral class
(and possibly department) 		Silicates and germanates - chain and band silicates
System no. to Strunz
and to Dana 		9.DG.85 ( 8th edition : VIII / F.35)
70.02.01.01
Crystallographic Data
Crystal system triclinic
Crystal class ; symbol triclinic pinacoidal; 1
Room group (no.) P 1 (No. 2)
Lattice parameters a  = 10.10  Å ; b  = 7.38 Å; c  = 16.01 Å,
α  = 96.4 °; β  = 76.6 °; γ  = 111.1 °
Formula units Z  = 2
Twinning lamellar
Physical Properties
Mohs hardness 5.5 to 6
Density (g / cm 3 ) measured: 2.84 to 2.93; calculated: 2.80
Cleavage perfect after {100}, imperfect after {010}
Break ; Tenacity slightly scalloped to uneven
colour red brown, raspberry red, pink
Line color White
transparency transparent to translucent
shine Glass gloss
Crystal optics
Refractive indices n α  = 1.576 to 1.587
n β  = 1.583 to 1.589
n γ  = 1.591 to 1.594
Birefringence δ = 0.007
Optical character biaxial positive

Miserite is a rarely occurring mineral from the mineral class of " silicates and germanates ". It crystallizes in the triclinic crystal system with the chemical composition KCa 5 □ [OH | F | S 2 O 7 | Si 6 O 15 ], so it is a potassium - calcium silicate with additional fluorine and hydroxide ions . Structurally it belongs to the chain and band silicates (inosilicates). The symbol □ indicates that this structure space is not fully occupied.

Miserite usually develops fine-grained to prismatic crystals , but also occurs in fissile masses of red-brown, raspberry-red or pink color. However, similar to rhodochrosite, miserite leaves a white line on the marking board . Its crystals are transparent to translucent and have a glass-like sheen .

With a Mohs hardness of 5.5 to 6, miserite is still one of the medium-hard minerals that, like the reference mineral orthoclase, can still be scratched with a steel file .

Etymology and history

Miserite was first discovered in the North Wilson quarry of the Union Carbide Vanadium Mine near Wilson Springs in Garland County in the US state of Arkansas.

The mineral was described in 1950 by Waldemar Theodore Schaller , who named it after the geologist and employee of the USGS Hugh Dinsmore Miser (1884–1969). Schaller thus corrected a description previously made by J. Francis Williams in 1891, who mistakenly believed the mineral to be a sodium-rich analogue of xonotlite and accordingly designated it as natroxonotlite .

classification

In the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the miserite belonged to the division of "chain silicates and band silicates (inosilicates)", where together with canasite , charoite , eveslogite , fluorcanasite , frankamenite and yuksporite, it belongs to the unnamed group VIII / F.35 made.

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 classifies miserite in the category of "chain and band silicates (inosilicates)". However, this is further subdivided according to the structure of the chain formation, so that the mineral can be found according to its structure in the sub-section "Chain and band silicates with 3-periodic single and multiple chains", where the unnamed group 9.DG. 85 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the miserite to the class of “silicates and Germanates”, but there in the more finely subdivided section of “chain silicates: columnar or tube structures”. Here it can be found together with Frankamenit in the unnamed group 70.02.01 within the subsection " Chain silicates: column or tube structures with Si2O7 dimers ".

Education and Locations

Miserite (pink) with pectolite (white) from the Union Carbide Mine, Wilson Springs, Garland County , Arkansas, USA (field of view 2.5 mm)

Miserite forms in metamorphic shale in contact with nepheline - syenite - dykes , but also in carbonatite or quartz - albite - aegirine - veins or albitite syenites. As accompanying minerals may include Baratovit , Ekanit , Eudialyt , fluorite , hornblende , mosandrite , orthoclase , scapolite , titanite and wollastonite occur.

As a rare mineral formation, miserite could only be detected at a few sites, whereby so far (as of 2013) around 15 sites are known. In addition to its type locality , the “North Wilson” quarry in Arkansas, the mineral has so far only been in the marathon in the United States of America (USA) from Wind Mountain in Otero County (New Mexico) as well as from the Wausau Plateau and the “Rotten granite” quarry County (Wisconsin).

Other previously known sites include Les Lacs-du-Témiscamingue in the municipality of Témiscamingue and the “Poudrette” quarry on Mont Saint-Hilaire in Canada, the Khodzhaachkan massif in the Soʻxtal ( Sokh Valley ) in the Alai mountains of Kyrgyzstan, the Murun -Massif and the Yakokut massif in the Aldan highlands in eastern Siberia as well as the Chergiles near Chekunda in the Far Eastern region of Khabarovsk in Russia and the Dara-i-Pioz (Darai-Pioz) glacier in the Alai mountains in Tajikistan.

Crystal structure

Miserite crystallizes triclinic in the space group P 1 (space group no. 2) with the lattice parameters a  = 10.10  Å ; b  = 7.38 Å; c  = 16.01 Å; α = 96.4 °; β = 76.6 ° and γ = 111.1 ° as well as two formula units per unit cell .

See also

literature

Web links

Commons : Miserite  - collection of pictures, videos and audio files

Individual evidence

  1. ↑ a b c d e Hugo Strunz , Ernest H. Nickel: Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p.  641 .
  2. ↑ a b c Miserite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 75.1 kB )
  3. ↑ Mindat - Miserite
  4. ↑ Mindat - Number of localities for Miserit
  5. ↑ Find location list for miserite at the Mineralienatlas and at Mindat