Cyanochroite
A valid IMA mineral species - grandfathered
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About Cyanochroite
Formula:
K2Cu(SO4)2 · 6H2O
Colour:
Greenish-blue
Lustre:
Vitreous
Hardness:
2 - 2½
Specific Gravity:
2.224
Crystal System:
Monoclinic
Member of:
Name:
From the Greek κυανός for "blue" and χρώσις for "colouring", in allusion to the color.
Unique Identifiers
Mindat ID:
1200
Long-form identifier:
mindat:1:1:1200:9
IMA Classification of Cyanochroite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
K2Cu2+(S6+O4)2·6H2O
Type description reference:
Classification of Cyanochroite
7.CC.60
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
C : Sulfates (selenates, etc.) without additional anions, with H2O
C : With medium-sized and large cations
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
C : Sulfates (selenates, etc.) without additional anions, with H2O
C : With medium-sized and large cations
29.3.6.2
29 : HYDRATED ACID AND NORMAL SULFATES
3 : A2B(XO4)2·xH2O
29 : HYDRATED ACID AND NORMAL SULFATES
3 : A2B(XO4)2·xH2O
25.2.15
25 : Sulphates
2 : Sulphates of Cu and Ag
25 : Sulphates
2 : Sulphates of Cu and Ag
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 |
|---|---|---|
| Cyc | 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 Cyanochroite
Vitreous
Transparency:
Transparent
Colour:
Greenish-blue
Hardness:
2 - 2½ on Mohs scale
Cleavage:
Perfect
{201}, perfect.
{201}, perfect.
Density:
2.224 g/cm3 (Measured) 2.23 g/cm3 (Calculated)
Comment:
Measured on artificial material.
Optical Data of Cyanochroite
Type:
Biaxial (+)
RI values:
nα = 1.4836 nβ = 1.4864 nγ = 1.502
2V:
Measured: 46° , Calculated: 48°
Max. Birefringence:
δ = 0.018
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:
r > v to r < v strong
Chemistry of Cyanochroite
Mindat Formula:
K2Cu(SO4)2 · 6H2O
Element Weights:
Crystallography of Cyanochroite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Setting:
P21/c
Cell Parameters:
a = 9.09 Å, b = 12.14 Å, c = 6.18 Å
β = 104.47°
β = 104.47°
Ratio:
a:b:c = 0.749 : 1 : 0.509
Unit Cell V:
660.35 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Crystals tabular {001}. CVrystalline crusts.
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
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Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
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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) |
|---|---|---|---|---|---|---|---|
| 0004780 | Cyanochroite | Bosi F, Belardi G, Ballirano P (2009) Structural features in Tutton's salts K2[M2+(H2O)6](SO4)2, with M2+= Mg, Fe, Co, Ni, Cu, and Zn American Mineralogist 94 74-82 |  | 2009 | synthetic | 0 | 293 |
| 0012326 | Cyanochroite | Robinson D J, Kennard C H L (1972) Potassium hexa-aquacopper(II) sulfate, CuH12K2O14S2 (neutron) Crystal Structure Communications 1 185-188 | 1972 | synthetic | 0 | 293 | |
| 0019590 | Cyanochroite | Carapezza M, Di Sanseverino L R (1968) Crystallography and genesis of double sulfates and their hydrates. II. Structure, powder pattern and thermoanalysis of cyanochroite, K2Cu(SO4)2*6H2O Mineralogica Petrographica Acta 14 23-37 | 1968 | synthetic | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.673 Å | (100) |
| 4.179 Å | (90) |
| 4.057 Å | (79) |
| 2.975 Å | (65) |
| 2.377 Å | (45) |
| 2.816 Å | (42) |
| 2.993 Å | (39) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 25 : Evaporites (prebiotic) | |
| Stage 7: Great Oxidation Event | <2.4 |
| 45a : [Sulfates, arsenates, selenates, antimonates] | |
| 45b : [Other oxidized fumarolic minerals] | |
| 47a : [Near-surface hydration of prior minerals] | |
| 47b : [Sulfates and sulfites] | |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 55 : Anthropogenic mine minerals | |
| 56 : Slag and smelter minerals (see also #51 and #55) |
Type Occurrence of Cyanochroite
Place of Conservation of Type Material:
Natural History Museum, Paris, France, 175.358.
Geological Setting of Type Material:
Active volcanic fumaroles.
Synonyms of Cyanochroite
Other Language Names for Cyanochroite
Relationship of Cyanochroite to other Species
Member of:
Other Members of Picromerite Group:
| Boussingaultite | (NH4)2Mg(SO4)2 · 6H2O | Mon. 2/m : P21/b |
| Katerinopoulosite | (NH4)2Zn(SO4)2 · 6H2O | Mon. 2/m : P21/b |
| Mohrite | (NH4)2Fe(SO4)2 · 6H2O | Mon. 2/m : P21/b |
| Nickelboussingaultite | (NH4)2Ni(SO4)2 · 6H2O | Mon. 2/m : P21/b |
| Nickelpicromerite | K2Ni(SO4)2 · 6H2O | Mon. 2/m : P21/b |
| Picromerite | K2Mg(SO4)2 · 6H2O | Mon. 2/m : P2/b |
Related Minerals - Strunz-mindat Grouping
| 7.CC. | Cobaltoblödite | Na2Co(SO4)2 · 4H2O |
| 7.CC. | Andychristyite | PbCu2+Te6+O5(H2O) |
| 7.CC. | Ammoniovoltaite | (NH4)2Fe2+5Fe3+3Al(SO4)12(H2O)18 |
| 7.CC.05 | Krausite | KFe(SO4)2 · H2O |
| 7.CC.10 | Tamarugite | NaAl(SO4)2 · 6H2O |
| 7.CC.15 | Mendozite | NaAl(SO4)2 · 11H2O |
| 7.CC.15 | Kalinite | KAl(SO4)2 · 11H2O |
| 7.CC.20 | Alum-(Na) | NaAl(SO4)2 · 12H2O |
| 7.CC.20 | Lonecreekite | (NH4)Fe3+(SO4)2 · 12H2O |
| 7.CC.20 | Alum-(K) | KAl(SO4)2 · 12H2O |
| 7.CC.20 | Tschermigite | (NH4)Al(SO4)2 · 12H2O |
| 7.CC.20 | Lanmuchangite | Tl+Al(SO4)2 · 12H2O |
| 7.CC.25 | Zincovoltaite | K2Zn5Fe3+3Al(SO4)12 · 18H2O |
| 7.CC.25 | Voltaite | K2Fe2+5Fe3+3Al(SO4)12 · 18H2O |
| 7.CC.25 | Magnesiovoltaite | K2Mg5Fe3+3Al(SO4)12 · 18H2O |
| 7.CC.25 | Pertlikite | K2(Fe2+,Mg)2(Mg,Fe3+)4Fe3+2Al(SO4)12 · 18H2O |
| 7.CC.25 | Ammoniomagnesiovoltaite | (NH4)2Mg2+5Fe3+3Al(SO4)12 · 18H2O |
| 7.CC.30 | Kröhnkite | Na2Cu(SO4)2 · 2H2O |
| 7.CC.35 | Ferrinatrite | Na3Fe(SO4)3 · 3H2O |
| 7.CC.40 | Goldichite | KFe(SO4)2 · 4H2O |
| 7.CC.45 | Löweite | Na12Mg7(SO4)13 · 15H2O |
| 7.CC.50 | Nickelblödite | Na2Ni(SO4)2 · 4H2O |
| 7.CC.50 | Blödite | Na2Mg(SO4)2 · 4H2O |
| 7.CC.50 | Changoite | Na2Zn(SO4)2 · 4H2O |
| 7.CC.55 | Leonite | K2Mg(SO4)2 · 4H2O |
| 7.CC.55 | Mereiterite | K2Fe(SO4)2 · 4H2O |
| 7.CC.60 | Nickelpicromerite | K2Ni(SO4)2 · 6H2O |
| 7.CC.60 | Nickelboussingaultite | (NH4)2Ni(SO4)2 · 6H2O |
| 7.CC.60 | Katerinopoulosite | (NH4)2Zn(SO4)2 · 6H2O |
| 7.CC.60 | Picromerite | K2Mg(SO4)2 · 6H2O |
| 7.CC.60 | Mohrite | (NH4)2Fe(SO4)2 · 6H2O |
| 7.CC.60 | Boussingaultite | (NH4)2Mg(SO4)2 · 6H2O |
| 7.CC.65 | Polyhalite | K2Ca2Mg(SO4)4 · 2H2O |
| 7.CC.70 | Leightonite | K2Ca2Cu(SO4)4 · 2H2O |
| 7.CC.75 | Amarillite | NaFe(SO4)2 · 6H2O |
| 7.CC.80 | Konyaite | Na2Mg(SO4)2 · 5H2O |
| 7.CC.85 | Wattevilleite | Na2Ca(SO4)2 · 4H2O (?) |
| 7.CC.85 | Xocolatlite | Ca2Mn4+2(Te6+O6)2 · H2O |
| 7.CC.90 | Eckhardite | (Ca,Pb)Cu2+Te6+O5(H2O) |
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) | 17.6932% | 5,485 | 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
Special Storage/
Display Requirements:
Display Requirements:
Water soluble
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 Cyanochroite
mindat.org URL:
https://www.mindat.org/min-1200.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Cyanochroite
Reference List:
Localities for Cyanochroite
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.
Canada | |
| Traill (1983) |
Costa Rica | |
| Ulloa et al. (2018) |
Greece | |
| 42. +2 other references |
Italy (TL) | |
| Russo +1 other reference |
| Pelloux (1927) +1 other reference | |
| Pellino et al. (2025) | |
Poland | |
| Cu +2 other references |
Russia | |
| Pavel M. Kartashov (n.d.) |
| Pekov et al. (2012) | |
| Sharygin et al. (2018) |
Quick NavTopAbout CyanochroiteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesRelationshipsStrunz-MindatRadioactivityOther InformationInternet Links References Localities Locality List
Yadovitaya fumarole, Second scoria cone, Northern Breakthrough, Great Fissure eruption, Tolbachik Volcanic field, Milkovsky District, Kamchatka Krai, Russia