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]
| Klöchite | |
|---|---|
| General | |
| Category | Osumilite |
| Formula (repeating unit) | K◻2(Fe2+Fe3+)Zn3[Si12O30] |
| IMA symbol | Klö |
| Strunz classification | 9.CM.05
9 : Silicates C : Cyclosilicates M : [Si6O18]12- 6-membered double rings |
| Crystal system | Hexagonal |
| Crystal class | 6/mmm (6/m 2/m 2/m) - Dihexagonal Dipyramidal |
| Space group | P6/mcc |
| Unit cell | a = 10.120 Å, c = 14.298 Å |
| Identification | |
| Color | Blue, Bright Orange |
| Cleavage | None Observed |
| Luster | Vitreous |
| Specific gravity | 3.007 |
| Density | 3.007 g/cm3 |
| Optical properties | Uniaxial negative |
| Refractive index | nω = 1.594 nε = 1.590 |
| References | [1][2] |
Occurrence
editKlöchite 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
editKlöchite 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
editKlöchite has a blue coloring, with a vitreous luster. It is also found to be translucent and is not fluorescent.[2]
Chemical composition
edit| 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 |
X-ray crystallography
editLimited 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
editReferences
edit- ^ a b c d e f 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. Bibcode:2011CaMin..49.1115B. doi:10.3749/canmin.49.4.1115.
- ^ a b c d KLÖCHITE: Mineral information, data and localities. - mindat.org Mindat, https://www.mindat.org/min-35832.html (accessed December 2023).