Hieratite
A valid IMA mineral species - grandfathered
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About Hieratite
Formula:
K2[SiF6]
Colour:
Colourless, white, grey; Colourless in transmitted light.
Lustre:
Vitreous
Hardness:
2½
Specific Gravity:
2.665
Crystal System:
Isometric
Name:
Named by Alfonso Cossa in 1881 after the type locality of Volcano, Italy. The name Vulcano, in ancient Greek, is Hiera.
Type Locality:
Dimorph of:
Isostructural with:
This page provides mineralogical data about Hieratite.
Unique Identifiers
Mindat ID:
1900
Long-form identifier:
mindat:1:1:1900:8
Similar Names
| Hartite | A synonym of Branchite | C20H34 |
| Harttite | A synonym of Svanbergite | SrAl3(PO4)(SO4)(OH)6 |
IMA Classification of Hieratite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
K2SiF6
Classification of Hieratite
3.CH.15
3 : HALIDES
C : Complex halides
H : Silicofluorides
3 : HALIDES
C : Complex halides
H : Silicofluorides
11.5.1.1
11 : HALIDE COMPLEXES
5 : AmBX6
11 : HALIDE COMPLEXES
5 : AmBX6
8.12.4
8 : Halides - Fluorides, Chlorides, Bromides and Iodides; also Fluoborates and Fluosilicates
12 : Fluorborates (BF'4) and fluosilicates (SiF''6)
8 : Halides - Fluorides, Chlorides, Bromides and Iodides; also Fluoborates and Fluosilicates
12 : Fluorborates (BF'4) and fluosilicates (SiF''6)
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 |
|---|---|---|
| Hie | 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 Hieratite
Vitreous
Transparency:
Transparent
Colour:
Colourless, white, grey; Colourless in transmitted light.
Hardness:
2½ on Mohs scale
Cleavage:
Perfect
on {111}
on {111}
Density:
2.665 g/cm3 (Measured) 2.668 g/cm3 (Calculated)
Optical Data of Hieratite
Type:
Isotropic
Chemistry of Hieratite
Mindat Formula:
K2[SiF6]
Element Weights:
Elements listed:
Crystallography of Hieratite
Crystal System:
Isometric
Class (H-M):
m3m (4/m 3 2/m) - Hexoctahedral
Space Group:
Fm3m
Cell Parameters:
a = 8.13 Å
Unit Cell V:
537.37 ų (Calculated from Unit Cell)
Morphology:
Crystals cubo-octahedral and octahedral. Stalactitic concretions, spongy to dense.
Crystal Structure
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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) |
|---|---|---|---|---|---|---|---|
| 0009880 | Hieratite | Hester J R, Maslen E N, Spadaccini N, Ishizawa N, Satow Y (1993) Accurate synchrotron radiation delta rho maps for K2SiF6 and K2PdCl6 Acta Crystallographica B49 967-973 |  | 1993 | synthetic | 0 | 293 |
| 0009879 | Hieratite | Hester J R, Maslen E N, Spadaccini N, Ishizawa N, Satow Y (1993) Accurate synchrotron radiation delta rho maps for K2SiF6 and K2PdCl6 Acta Crystallographica B49 967-973 | | 1993 | synthetic | 0 | 293 |
| 0009878 | Hieratite | Hester J R, Maslen E N, Spadaccini N, Ishizawa N, Satow Y (1993) Accurate synchrotron radiation delta rho maps for K2SiF6 and K2PdCl6 Acta Crystallographica B49 967-973 | | 1993 | synthetic | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 4.699 Å | (100) |
| 2.349 Å | (70) |
| 2.877 Å | (65) |
| 2.034 Å | (50) |
| 1.438 Å | (16) |
| 1.565 Å | (14) |
| 1.661 Å | (12) |
Comments:
Synthetic. Data from Swanson et al. (1955).
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 45b : [Other oxidized fumarolic minerals] | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 49 : Oxic cellular biomineralization (see also #44) | <0.54 |
| 50 : Coal and/or oil shale minerals | <0.36 |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 54 : Coal and other mine fire minerals (see also #51 and #56) |
Type Occurrence of Hieratite
Place of Conservation of Type Material:
No designated type material.
Geological Setting of Type Material:
Active volcanic fumaroles.
Associated Minerals at Type Locality:
Other Language Names for Hieratite
Common Associates
Associations Based on Photo Data:
| 3 photos of Hieratite associated with Demartinite | K2[SiF6] |
| 1 photo of Hieratite associated with Knasibfite | K3Na4[SiF6]3[BF4] |
Related Minerals - Strunz-mindat Grouping
| 3.CH.05 | Malladrite | Na2[SiF6] |
| 3.CH.10 | Bararite | (NH4)2[SiF6] |
| 3.CH.15 | Cryptohalite | (NH4)2[SiF6] |
| 3.CH.20 | Demartinite | K2[SiF6] |
| 3.CH.25 | Knasibfite | K3Na4[SiF6]3[BF4] |
| 3.CH.30 | Heklaite | KNaSiF6 |
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) | 35.4999% | 11,005 | 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
Other Information
Notes:
Soluble in cold water; more so in hot water.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Industrial Uses:
None
Internet Links for Hieratite
mindat.org URL:
https://www.mindat.org/min-1900.html
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References for Hieratite
Reference List:
Cossa, Alfonso (1882) Sur la Hiératite, espèce minérale nouvelle. Bulletin de Minéralogie, 5 (2) 61-62 doi:10.3406/bulmi.1882.1699
Goßner, B.; Kraus, O. (1934) Das Kristallgitter von Ammoniumhexafluorosilikat (NH4)2SiF6. Zeitschrift für Kristallographie, Mineralogie und Petrographie, 88 (1-6). 223-225 doi:10.1524/zkri.1934.88.1.223
Ketelaar, J. A. A. (1935) Die Kristallstruktur von K-, Rb-, Cs- und Tl-Silicofluorid und von LiMnO4.3H2O. Zeitschrift für Kristallographie - Crystalline Materials, 92 (1) 155-156 doi:10.1524/zkri.1935.92.1.155
Denaeyer, Marcel E., Ledent, D. (1952) Sur la présence de la modification hexagonale de la hiératite (camermanite) dans des incrustations de sels potassiques d'une cheminée d'usine. Bulletin de Minéralogie, 75 (4) 231-236 doi:10.3406/bulmi.1952.4772
Sclar, Charles B., Fahey, Joseph J. (1972) The staining mechanism of potassium feldspar and the origin of hieratite. American Mineralogist, 57 (1-2) 287-291
Localities for Hieratite
Showing 9 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.
Antarctica | |
| Kammerer (2011) |
DR Congo | |
| Bailey (1980) |
France | |
| Vlastélic et al. (2013) |
Iceland | |
| Garavelli et al. (2010) |
Italy | |
| Palache et al. (1951) |
| Pelloux (1927) +1 other reference | |
| Cossa (1881-1882) |
Saint Helena， Ascension and Tristan da Cunha | |
| Bailey (1980) | |
USA | |
| M.E. Ciriotti (2006) |
Quick NavTopAbout HieratiteUnique IdentifiersSimilar NamesIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence Other LanguagesCommon AssociatesStrunz-MindatRadioactivityOther InformationInternet Links References Localities Locality List
La Fossa crater, Vulcano Island, Lipari, Eolie Islands, Metropolitan City of Messina, Sicily, Italy