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Steklite
A valid IMA mineral species
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About Steklite
Formula:
KAl(SO4)2
Colour:
colorless
Lustre:
Vitreous
Hardness:
2½
Specific Gravity:
2.792 (Calculated)
Crystal System:
Trigonal
Name:
From the Russian word стекло (steklo) for glass as an allusion to the visual appearance of aggregates of the mineral formed around vents of a burning coal heap (coal mine N 47 near Kopeisk, South Urals, Russia).
K-analogue of godovikovite.
Found on a burnt coal dump, so first considered to be anthropogenic and not to be a true mineral.
Steklite is a natural analog of the synthetic KAl(SO4)2 studied by Manoli et al (1970).
Found on a burnt coal dump, so first considered to be anthropogenic and not to be a true mineral.
Steklite is a natural analog of the synthetic KAl(SO4)2 studied by Manoli et al (1970).
Unique Identifiers
Mindat ID:
40128
Long-form identifier:
mindat:1:1:40128:7
Similar Names
IMA Classification of Steklite
Approved
IMA Formula:
KAl(S6+O4)2
Approval year:
2011
Approval history:
First published without approval in 1995, then approved in 2011 from a natural occurrence (Yadovitaya fumarole, Tolbachik volcano).
Type description reference:
Murashko, M. N., Pekov, I. V., Krivovichev, S. V., Chernyatyeva, A. P., Yapaskurt, V. O., Zadov, A. E., Zelensky, M. E. (2013) Steklite, KAl(SO4)2: A finding at the Tolbachik Volcano, Kamchatka, Russia, validating its status as a mineral species and crystal structure. Geology of Ore Deposits, 55 (7) 594-600 doi:10.1134/s1075701513070088
Classification of Steklite
7.AC.20
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
A : Sulfates (selenates, etc.) without additional anions, without H2O
C : With medium-sized and large cations
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
A : Sulfates (selenates, etc.) without additional anions, without H2O
C : With medium-sized and large cations
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Sek | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Steklite
Vitreous
Transparency:
Transparent
Colour:
Colorless
Comment:
aggregates are white to grayish white
Streak:
White
Hardness:
2½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
parallel to {001}
parallel to {001}
Fracture:
Micaceous
Comment:
Fracture is lamellar while very thin flakes are flexible.
Density:
2.792 g/cm3 (Calculated)
Optical Data of Steklite
Type:
Uniaxial (-)
RI values:
nω = 1.546(2) nε = 1.533(3)
Max. Birefringence:
δ = 0.013
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
None to Very Low
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Pleochroism:
Non-pleochroic
Chemistry of Steklite
Mindat Formula:
KAl(SO4)2
Element Weights:
Elements listed:
Crystallography of Steklite
Crystal System:
Trigonal
Class (H-M):
32 - Trapezohedral
Space Group:
P321
Cell Parameters:
a = 4.7281(3) Å, c = 7.9936(5) Å
Ratio:
a:c = 1 : 1.691
Unit Cell V:
154.76 ų (Calculated from Unit Cell)
Z:
1
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
Stop | Start
Labels
Console Off | On | Grey | Yellow
Console Off | On | Grey | Yellow
Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0018101 | Steklite | Vegard L, Maurstad A (1928) Die Kristallstruktur der wasserfreien Alaune R'R'''(SO4)2 _cod_database_code 1011235 Skrifter utgitt av det Norske Videnskaps-Akademi i Oslo 1928 1-24 | 1928 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 8.02 Å | (34) |
| 4.085 Å | (11) |
| 3.649 Å | (100) |
| 2.861 Å | (51) |
| 2.660 Å | (19) |
| 2.364 Å | (25) |
| 2.267 Å | (14) |
| 1.822 Å | (12) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 45a : [Sulfates, arsenates, selenates, antimonates] | |
| 45b : [Other oxidized fumarolic minerals] | |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 54 : Coal and other mine fire minerals (see also #51 and #56) |
Type Occurrence of Steklite
General Appearance of Type Material:
Hexagonal plates and more frequently multi!angular irregular lamellae. The both are commonly 5–10 µm and occasionally up to 30 µm in thickness; 0.2 mm and rarely up to 1 mm across
Place of Conservation of Type Material:
Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, registration number 4109/1
Geological Setting of Type Material:
Burnt coal dump
Fumarole
Fumarole
Associated Minerals at Type Locality:
Reference:
Murashko, M. N., Pekov, I. V., Krivovichev, S. V., Chernyatyeva, A. P., Yapaskurt, V. O., Zadov, A. E., Zelensky, M. E. (2013) Steklite, KAl(SO4)2: A finding at the Tolbachik Volcano, Kamchatka, Russia, validating its status as a mineral species and crystal structure. Geology of Ore Deposits, 55 (7) 594-600 doi:10.1134/s1075701513070088
Synonyms of Steklite
Other Language Names for Steklite
Common Associates
Associations Based on Photo Data:
| 1 photo of Steklite associated with Euchlorine | KNaCu3(SO4)3O |
Related Minerals - Strunz-mindat Grouping
| 7.AC. | Aluminopyracmonite | (NH4)3Al(SO4)3 |
| 7.AC. | Amgaite | Tl+32Te6+O6 |
| 7.AC.05 | Vanthoffite | Na6Mg(SO4)4 |
| 7.AC.08 | Pyracmonite | (NH4)3Fe(SO4)3 |
| 7.AC.10 | Langbeinite | K2Mg2(SO4)3 |
| 7.AC.10 | Efremovite | (NH4)2Mg2(SO4)3 |
| 7.AC.10 | Ferroefremovite | (NH4)2Fe2+2(SO4)3 |
| 7.AC.10 | Manganolangbeinite | K2Mn2(SO4)3 |
| 7.AC.15 | Yavapaiite | KFe3+(S6+O4)2 |
| 7.AC.15 | Eldfellite | NaFe3+(SO4)2 |
| 7.AC.20 | Sabieite | (NH4)Fe3+(SO4)2 |
| 7.AC.20 | Godovikovite | (NH4)Al(SO4)2 |
| 7.AC.35 | Aphthitalite | K3Na(SO4)2 |
| 7.AC.35 | Belomarinaite | KNa(SO4) |
| 7.AC.35 | Natroaphthitalite | KNa3(SO4)2 |
| 7.AC.35 | Möhnite | (NH4)K2Na(SO4)2 |
| 7.AC.40 | Itelmenite | Na4Mg3Cu3(SO4)8 |
| 7.AC.45 | Saranchinaite | Na2Cu(SO4)2 |
| 7.AC.50 | Majzlanite | K2Na(ZnNa)Ca(SO4)4 |
| 7.AC.60 | Philoxenite | (K,Na,Pb)4(Na,Ca)2(Mg,Cu)3(Fe3+0.5Al0.5)(SO4)8 |
| 7.AC.75 | Petrovite | Na12Cu2(SO4)8 |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 0.0000% | 0 | α, β, γ |
| Thorium (Th) | 0.0000% | 0 | α, β, γ |
| Potassium (K) | 15.1423% | 4,694 | β, γ |
For comparison:
- Banana: ~15 Bq per fruit
- Granite: 1,000–3,000 Bq/kg
- EU exemption limit: 10,000 Bq/kg
Note: Risk is shown relative to daily recommended maximum exposure to non-background radiation of 1000 µSv/year. Note that natural background radiation averages around 2400 µSv/year so in reality these risks are probably extremely overstated! With infrequent handling and safe storage natural radioactive minerals do not usually pose much risk.
Interactive Simulator:
Note: The mass selector refers to the mass of radioactive mineral present, not the full specimen, also be aware that the matrix may also be radioactive, possibly more radioactive than this mineral!
Activity: –
| Distance | Dose rate | Risk |
|---|---|---|
| 1 cm | ||
| 10 cm | ||
| 1 m |
The external dose rate (D) from a radioactive mineral is estimated by summing the gamma radiation contributions from its Uranium, Thorium, and Potassium content, disregarding daughter-product which may have a significant effect in some cases (eg 'pitchblende'). This involves multiplying the activity (A, in Bq) of each element by its specific gamma ray constant (Γ), which accounts for its unique gamma emissions. The total unshielded dose at 1 cm is then scaled by the square of the distance (r, in cm) and multiplied by a shielding factor (μshield). This calculation provides a 'worst-case' or 'maximum risk' estimate because it assumes the sample is a point source and entirely neglects any self-shielding where radiation is absorbed within the mineral itself, meaning actual doses will typically be lower. The resulting dose rate (D) is expressed in microsieverts per hour (μSv/h).
D = ((AU × ΓU) + (ATh × ΓTh) + (AK × ΓK)) / r2 × μshield
Fluorescence of Steklite
none
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Steklite
mindat.org URL:
https://www.mindat.org/min-40128.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Steklite
Reference List:
Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2011) New minerals and nomenclature modifications approved in 2011, CNMNC Newsletter No. 10. Mineralogical Magazine, 75 (5) 2549-2561 doi:10.1180/minmag.2011.075.5.2549
Murashko, M. N., Pekov, I. V., Krivovichev, S. V., Chernyatyeva, A. P., Yapaskurt, V. O., Zadov, A. E., Zelensky, M. E. (2013) Steklite, KAl(SO4)2: A finding at the Tolbachik Volcano, Kamchatka, Russia, validating its status as a mineral species and crystal structure. Geology of Ore Deposits, 55 (7) 594-600 doi:10.1134/s1075701513070088
Localities for Steklite
Showing 10 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Cape Verde | |
| Silva et al. (2019) |
Czech Republic | |
| Matýsek et al. (2022) |
Italy | |
| Pellino et al. (2025) |
Poland | |
| Kruszewski (2012) |
| Kruszewski et al. (2020) |
Russia | |
| Cesnokov et al. (1998) |
| Pekov (1998) |
| Pekov et al. (2018) |
| Williams et al. (2011) +2 other references |
USA | |
| Lapham et al. (1980) |
Quick NavTopAbout StekliteUnique IdentifiersSimilar NamesIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatRadioactivityFluorescence Other InformationInternet Links References Localities Locality List
Yadovitaya fumarole, Second scoria cone, Northern Breakthrough, Great Fissure eruption, Tolbachik Volcanic field, Milkovsky District, Kamchatka Krai, Russia