Chemistry:Klöchite

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Klöchite
General
CategoryOsumilite
Formula
(repeating unit)
K◻2(Fe2+Fe3+)Zn3[Si12O30]
Strunz classification9.CM.05

9 : Silicates C : Cyclosilicates

M : [Si6O18]12- 6-membered double rings
Crystal systemHexagonal
Crystal class6/mmm (6/m 2/m 2/m) - Dihexagonal Dipyramidal
Space groupP6/mcc
Unit cella = 10.120 Å, c = 14.298 Å
Identification
ColorBlue, Bright Orange
CleavageNone Observed
|re|er}}Vitreous
Specific gravity3.007
Density3.007 g/cm3
Optical propertiesUniaxial negative
Refractive indexnω = 1.594
nε = 1.590
References[1][2]

Klöchite is a cyclosilicate mineral of the Osumilite Group, found in a basalt quarry in Klöch, Austria. The basalt quarry it was found in is part of the Styrian Basin Volcanic Field in south-eastern Austria. Klöchite was found to be hosted in a xenolith primarily composed of quartz, sanidine, and diopside. Very few vesicles in the xenolith held Klöchite crystals, and only two samples were taken for study.[1]

Occurrence

Klöchite was found at the Klöch volcano in south-east Austria. The town of Klöch has a basalt mine, where a SiO2-rich xenolith protrudes. Small vesicles in the xenolith are found to host titanite, enstatite, forsterite, and other minerals including klöchite.[1] Klöchite has also been found in the town of Porto da Cruz, Madeira, Portugal, in a gabbro outcrop.[2]

Physical properties

Klöchite is seen as a flattened, hexagonal crystal. It has a maximum thickness of 0.01 mm and diameter of 0.3 mm. Due to a limited amount of samples, the streak and hardness were not determined for Klöchite.[1]

Optical properties

Klöchite has a blue coloring, with a vitreous luster. It is also found to be translucent and is not fluorescent.[2]

Chemical composition

Element wt% Range
Si 29.29 28.84 - 29.55
Zn 14.91 14.16 - 15.81
Fe 8.46 7.89 2 - 8.79
K 2.64 2.53 - 2.67
Mn 1.31 1.22 2 - 1.39
Na 1.09 0.88 - 1.51

[1]

X-ray crystallography

Limited samples of Klöchite mean that powder x-ray diffraction was not able to be performed, but the group of scientists who discovered the mineral performed a simulated powder diffraction. Single crystal X-ray diffraction was carried out, and the space group P6/mcc was determined from the intensity and absences in the data. The simulated diffraction was compared to x-ray diffraction data of milarite group mineral darapiosite. Klöchite's crystal structure has a silicate tetrahedral ring structure like other cyclosilicates, with iron cation octahedra and zinc atoms connecting the silicate rings.[1][2]

See also

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 Bojar, H.-P.; Walter, F.; Hauzenberger, C.; Postl, W. (1 August 2011). "KLOCHITE, K 2(Fe2+Fe3+)Zn3[Si12O30], A NEW MILARITE-TYPE MINERAL SPECIES FROM THE KLOCH VOLCANO, STYRIA, AUSTRIA". The Canadian Mineralogist 49 (4): 1115–1124. doi:10.3749/canmin.49.4.1115. Bibcode2011CaMin..49.1115B. 
  2. 2.0 2.1 2.2 2.3 KLÖCHITE: Mineral information, data and localities. - mindat.org Mindat, https://www.mindat.org/min-35832.html (accessed December 2023).