Thermessaite
A valid IMA mineral species
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About Thermessaite
Formula:
K2AlF3(SO4)
Colour:
colourless to white
Lustre:
Vitreous
Specific Gravity:
2.77
Crystal System:
Orthorhombic
Name:
Named after Thermessa, an ancient Greek name of the island of Vulcano meaning "the warm island".
Type Locality:
Isostructural with:
The K-analogue of thermessaite-(NH4).
This mineral contains linear infinite chains of repeating (AlF3) units, classifying it as a so-called ino-fluoro-aluminate.
This mineral contains linear infinite chains of repeating (AlF3) units, classifying it as a so-called ino-fluoro-aluminate.
Unique Identifiers
Mindat ID:
32287
Long-form identifier:
mindat:1:1:32287:4
Similar Names
| Thermessaite-(NH4) | A valid IMA mineral species | (NH4)2AlF3(SO4) |
IMA Classification of Thermessaite
Classification of Thermessaite
3.CG.25
3 : HALIDES
C : Complex halides
G : Aluminofluorides with CO3, SO4, PO4
3 : HALIDES
C : Complex halides
G : Aluminofluorides with CO3, SO4, PO4
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 |
|---|---|---|
| Tms | 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 Thermessaite
Vitreous
Transparency:
Transparent
Colour:
Colourless to white
Streak:
White
Hardness Data:
Could not be measured
Tenacity:
Brittle
Cleavage:
None Observed
Fracture:
None observed
Density:
2.77(2) g/cm3 (Measured) 2.790 g/cm3 (Calculated)
Comment:
from flotation at 25°C in bromoform-chloroform
Chemistry of Thermessaite
Mindat Formula:
K2AlF3(SO4)
Element Weights:
Crystallography of Thermessaite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pbcn
Cell Parameters:
a = 10.81 Å, b = 8.336 Å, c = 6.822 Å
Ratio:
a:b:c = 1.297 : 1 : 0.818
Unit Cell V:
614.75 ų (Calculated from Unit Cell)
Morphology:
Prismatic with {110} and the pinacoid {100} as the dominant forms, terminated by minor {111}.
Crystal Structure
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2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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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) |
|---|---|---|---|---|---|---|---|
| 0006194 | Thermessaite | Demartin F, Gramaccioli C M, Campostrini I, Orlandi P (2008) Thermessaite, K2[AlF3|SO4], a new ino-aluminofluoride-sulfate from La Fossa crater, Vulcano, Aeolian Islands, Italy The Canadian Mineralogist 46 693-700 |  | 2008 | La Fossa crater, Vulcano, Aeolian Islands, Italy | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 6.631 Å | (70) |
| 5.429 Å | (14) |
| 3.317 Å | (28) |
| 2.983 Å | (100) |
| 2.702 Å | (82) |
| 2.648 Å | (14) |
| 2.208 Å | (30) |
| 1.712 Å | (58) |
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 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 50 : Coal and/or oil shale minerals | <0.36 |
Type Occurrence of Thermessaite
General Appearance of Type Material:
sharp translucent crystals up to 0.25 mm
Place of Conservation of Type Material:
Referece Collection of Dipartimento di Chimica Strutturale e Stereochimica Inorganica of Universita degli Studi di Milano, Milan, Italy
Geological Setting of Type Material:
An altered pyroclastic breccia in active medium- to high-temperature fumaroles at the rim of La Fossa crater.
Associated Minerals at Type Locality:
Synonyms of Thermessaite
Other Language Names for Thermessaite
Common Associates
Associations Based on Photo Data:
| 2 photos of Thermessaite associated with Syngenite | K2Ca(SO4)2 · H2O |
| 2 photos of Thermessaite associated with Metavoltine | K2Na6Fe2+Fe3+6O2(SO4)12 · 18H2O |
| 2 photos of Thermessaite associated with Cossaite | (Mg0.5,◻)Al6(SO4)6(HSO4)F6 · 36H2O |
| 1 photo of Thermessaite associated with Vlodavetsite | AlCa2(SO4)2F2Cl · 4H2O |
Related Minerals - Strunz-mindat Grouping
| 3.CG.3.CG. | Chukhrovite-(Ca) | Ca3Ca1.5Al2(SO4)F13 · 12H2O |
| 3.CG.05 | Stenonite | Sr2Al(CO3)F5 |
| 3.CG.10 | Meniaylovite | Ca4[(SO4)(SiF6)(AlF6)]F · 12H2O |
| 3.CG.10 | Chukhrovite-(Ce) | Ca3CeAl2(SO4)F13 · 12H2O |
| 3.CG.10 | Chukhrovite-(Y) | Ca3YAl2(SO4)F13 · 12H2O |
| 3.CG.10 | Chukhrovite-(Nd) | Ca3NdAl2(SO4)F13 · 12H2O |
| 3.CG.15 | Creedite | Ca3Al2(SO4)(OH)2F8 · 2H2O |
| 3.CG.20 | Bøggildite | Na2Sr2Al2PO4F9 |
| 3.CG.25 | Thermessaite-(NH4) | (NH4)2AlF3(SO4) |
| 3.CG.30 | Kruijenite | Ca4Al4(SO4)F2(OH)16 · 2H2O |
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) | 30.2811% | 9,387 | 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 Thermessaite
none observed under both short- and long-wave
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 Thermessaite
mindat.org URL:
https://www.mindat.org/min-32287.html
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References for Thermessaite
Localities for Thermessaite
Showing 3 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.
Germany | |
| Witzke et al. (2015) |
Italy | |
| Balassone et al. (2019) |
| Demartin et al. (2008) |
Quick NavTopAbout ThermessaiteUnique IdentifiersSimilar NamesIMA Classification Classification Mineral SymbolsPhysical Properties Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatRadioactivityFluorescence Other InformationInternet Links References Localities Locality List
La Fossa crater, Vulcano Island, Lipari, Eolie Islands, Metropolitan City of Messina, Sicily, Italy