Erythrosiderite
A valid IMA mineral species - grandfathered
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About Erythrosiderite
Formula:
K2[Fe3+Cl5(H2O)]
Colour:
Ruby-red to red, brownish red; brown-red or yellowish in transmitted light.
Lustre:
Vitreous
Specific Gravity:
2.372
Crystal System:
Orthorhombic
Name:
From the Greek έρυθρός, red, and σίδηρος, iron, in allusion to the color and iron content.
Isostructural with:
Unique Identifiers
Mindat ID:
1408
Long-form identifier:
mindat:1:1:1408:9
IMA Classification of Erythrosiderite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
K2Fe3+Cl5·H2O
First published:
1872
Classification of Erythrosiderite
3.CJ.10
3 : HALIDES
C : Complex halides
J : With MX6 complexes; M = Fe, Mn, Cu
3 : HALIDES
C : Complex halides
J : With MX6 complexes; M = Fe, Mn, Cu
11.4.1.1
11 : HALIDE COMPLEXES
4 : AmBX5·xH2O
11 : HALIDE COMPLEXES
4 : AmBX5·xH2O
8.11.5
8 : Halides - Fluorides, Chlorides, Bromides and Iodides; also Fluoborates and Fluosilicates
11 : Halides of Fe and Ni
8 : Halides - Fluorides, Chlorides, Bromides and Iodides; also Fluoborates and Fluosilicates
11 : Halides of Fe and Ni
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 |
|---|---|---|
| Esd | 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 Erythrosiderite
Vitreous
Colour:
Ruby-red to red, brownish red; brown-red or yellowish in transmitted light.
Cleavage:
Perfect
On {201} and {011}.
On {201} and {011}.
Density:
2.372 g/cm3 (Measured)
Optical Data of Erythrosiderite
Type:
Biaxial (+)
RI values:
nα = 1.715 nβ = 1.75 nγ = 1.8
2V:
Measured: 62° , Calculated: 82°
Max. Birefringence:
δ = 0.085
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:
Moderate
Dispersion:
strong
Chemistry of Erythrosiderite
Mindat Formula:
K2[Fe3+Cl5(H2O)]
Element Weights:
Common Impurities:
Al
Crystallography of Erythrosiderite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pnma
Cell Parameters:
a = 9.7 Å, b = 13.58 Å, c = 7.01 Å
Ratio:
a:b:c = 0.714 : 1 : 0.516
Unit Cell V:
923.40 ų (Calculated from Unit Cell)
Morphology:
Crystals somewhat tabular {100}.
Twinning:
On [21_1] and [20_1] (artificial material).
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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Big Balls | Small Balls | Just Balls | Spacefill
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Display Options
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View
CIF File Best | x | y | z | a | b | c
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Rotation
Stop | Start
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Labels
Console Off | On | Grey | Yellow
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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) |
|---|---|---|---|---|---|---|---|
| 0010300 | Erythrosiderite | Schultz A J, Carlin R L (1995) Single-crystal pulsed neutron diffraction structure of the antiferromagnet K2[FeCl5(H2O)] with and without applied pressure Acta Crystallographica B51 43-47 |  | 1995 | synthetic | 0 | 293 |
| 0010299 | Erythrosiderite | Schultz A J, Carlin R L (1995) Single-crystal pulsed neutron diffraction structure of the antiferromagnet K2[FeCl5(H2O)] with and without applied pressure Acta Crystallographica B51 43-47 | | 1995 | synthetic | 0 | 293 |
| 0013271 | Erythrosiderite | Gabas M, Palacio F, Rodriguez-Carvajal J, Visser D (1995) Magnetic structures of the three-dimensional Heisenberg antiferromagnets K2FeCl5*(D2O) and Rb2FeCl5*(D2O) _cod_database_code 1006098 Journal of Physics: Condensed Matter 7 4725-4738 | 1995 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.782 Å | (100) |
| 5.566 Å | (40) |
| 2.427 Å | (40) |
| 5.68 Å | (35) |
| 2.440 Å | (25) |
| 2.993 Å | (19) |
| 2.841 Å | (16) |
Comments:
Synthetic
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 25 : Evaporites (prebiotic) | |
| Stage 7: Great Oxidation Event | <2.4 |
| 45b : [Other oxidized fumarolic minerals] |
Type Occurrence of Erythrosiderite
Geological Setting of Type Material:
Active volcanic fumaroles.
Associated Minerals at Type Locality:
Other Language Names for Erythrosiderite
Dutch:Erythrosideriet
German:Erythrosiderit
Italian:Eritrosiderite
Russian:Эритросидерит
Spanish:Erythrosiderita
Related Minerals - Strunz-mindat Grouping
| 3.CJ.05 | Rinneite | K3Na[FeCl6] |
| 3.CJ.05 | Saltonseaite | K3NaMnCl6 |
| 3.CJ.05 | Chlormanganokalite | K4[MnCl6] |
| 3.CJ.10 | Kremersite | (NH4,K)2[Fe3+Cl5(H2O)] |
| 3.CJ.15 | Mitscherlichite | K2CuCl4 · 2H2O |
| 3.CJ.20 | Douglasite | K2[Fe2+Cl4(OH2)2] |
| 3.CJ.25 | 'Redikortsevite' | (NH4)MgCl3 · 6H2O |
| 3.CJ.30 | Zirklerite | (Fe,Mg,Ca)9Al4Cl18(OH)12 · 14H2O (?) |
| 3.CJ.30 | Kalithallite | K3Tl3+Cl6 · 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) | 23.7447% | 7,361 | 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:
Very deliquescent. Readily soluble in 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.
Internet Links for Erythrosiderite
mindat.org URL:
https://www.mindat.org/min-1408.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Erythrosiderite
Localities for Erythrosiderite
Showing 14 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 | |
| Dietrich et al. (2004) |
| Dietrich et al. (2004) |
| Palache et al. (1951) |
Iran | |
| Talbot et al. (2009) |
Italy (TL) | |
| Palache et al. (1951) +1 other reference |
| Parascandola (1960) |
| Pelloux (1927) +5 other references | |
| - (n.d.) +1 other reference |
Poland | |
| Kruszewski (2012) |
Russia | |
| Sharygin et al. (2018) |
| Vergasova et al. (1977) +1 other reference |
Spain | |
| Campeny et al. (2023) |
USA | |
| Northrop et al. (1996) |
| Hawley +5 other references |
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Mount Vesuvius, Metropolitan City of Naples, Campania, Italy