Goldichite
A valid IMA mineral species - grandfathered
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About Goldichite
Samuel Stephen Goldich
Formula:
KFe(SO4)2 · 4H2O
Colour:
Pale yellowish green
Lustre:
Vitreous
Hardness:
2½
Specific Gravity:
2.43
Crystal System:
Monoclinic
Name:
Named in 1955 by Abraham Rosenzweig and Eugene B. Gross in honor of Dr. Samuel Stephen Goldich ["January", 1909 USA - December 20, 2000 Applewood, Colorado, USA], American mineralogist, University of Minnesota and founding chief of the USGS Branch of Isotope Geology. The Goldich Stability Series was devised by him.
This page provides mineralogical data about Goldichite.
Unique Identifiers
Mindat ID:
1722
Long-form identifier:
mindat:1:1:1722:6
IMA Classification of Goldichite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
KFe3+(SO4)2 · 4H2O
First published:
1955
Classification of Goldichite
7.CC.40
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
29.5.2.1
29 : HYDRATED ACID AND NORMAL SULFATES
5 : AB(XO4)2·xH2O
29 : HYDRATED ACID AND NORMAL SULFATES
5 : AB(XO4)2·xH2O
25.11.8
25 : Sulphates
11 : Sulphates of Fe and other metals
25 : Sulphates
11 : Sulphates of Fe and other metals
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 |
|---|---|---|
| Gol | 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 Goldichite
Vitreous
Transparency:
Transparent
Colour:
Pale yellowish green
Comment:
Lavender tint in artificial light.
Streak:
White
Hardness:
2½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
On {100}
On {100}
Density:
2.43 g/cm3 (Measured) 2.461 g/cm3 (Calculated)
Optical Data of Goldichite
Type:
Biaxial (+)
RI values:
nα = 1.582 - 1.584 nβ = 1.602(2) nγ = 1.629 - 1.639
2V:
Measured: 82° , Calculated: 75° to 82°
Max. Birefringence:
δ = 0.047 - 0.055
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.
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.
Surface Relief:
Moderate
Dispersion:
r > v strong
Optical Extinction:
X = b; Y ≃ a; Z ∧ c = 9°–11°.
Pleochroism:
Weak
Comments:
X= colorless
Y= colorless to pale yellow
Z= very pale yellow
Y= colorless to pale yellow
Z= very pale yellow
Chemistry of Goldichite
Mindat Formula:
KFe(SO4)2 · 4H2O
Element Weights:
Crystallography of Goldichite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Cell Parameters:
a = 10.387(6) Å, b = 10.486(6) Å, c = 9.086(5) Å
β = 101.68(7)°
β = 101.68(7)°
Ratio:
a:b:c = 0.991 : 1 : 0.866
Unit Cell V:
969.14 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Flattened on {100} and elongated along [001] with forms {100}, {110}, and
{011}.
{011}.
Crystallographic forms of Goldichite
Crystal Atlas:
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Goldichite - {100}, {110}, {011},
3d models and HTML5 code kindly provided by
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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) |
|---|---|---|---|---|---|---|---|
| 0000264 | Goldichite | Graeber E J, Rosenzweig A (1971) The crystal structures of yavapaiite, KFe(SO4)2, and goldichite, KFe(SO4)2.4H2O American Mineralogist 56 1917-1933 |  | 1971 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.068 Å | (100) |
| 7.35 Å | (90) |
| 10.29 Å | (80) |
| 6.85 Å | (70) |
| 4.00 Å | (60) |
| 3.403 Å | (60) |
| 2.656 Å | (60) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 45a : [Sulfates, arsenates, selenates, antimonates] | |
| 47a : [Near-surface hydration of prior minerals] | |
| 47b : [Sulfates and sulfites] | |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 55 : Anthropogenic mine minerals |
Geological Setting:
Oxidation of pyrite, rarely fumaroles.
Type Occurrence of Goldichite
General Appearance of Type Material:
Radiating clusters of pale-green crystals or fine-grained crystalline encrustations.
Place of Conservation of Type Material:
National Museum of Natural History (Smithsonian), Washington, D.C., USA, 106903.
Geological Setting of Type Material:
Cementing material of a talus slope below a small, pyrite-rich uranium deposit.
Associated Minerals at Type Locality:
Other Language Names for Goldichite
Common Associates
Associated Minerals Based on Photo Data:
| 29 photos of Goldichite associated with Coquimbite | AlFe3(SO4)6(H2O)12 · 6H2O |
| 16 photos of Goldichite associated with Römerite | Fe2+Fe3+2(SO4)4 · 14H2O |
| 10 photos of Goldichite associated with Halotrichite | FeAl2(SO4)4 · 22H2O |
| 9 photos of Goldichite associated with Voltaite | K2Fe2+5Fe3+3Al(SO4)12 · 18H2O |
| 4 photos of Goldichite associated with Ferricopiapite | Fe3+0.67Fe3+4(SO4)6(OH)2 · 20H2O |
| 3 photos of Goldichite associated with Krausite | KFe(SO4)2 · H2O |
| 2 photos of Goldichite associated with Copiapite | Fe2+Fe3+4(SO4)6(OH)2 · 20H2O |
| 1 photo of Goldichite associated with Melanterite | Fe2+(H2O)6SO4 · H2O |
| 1 photo of Goldichite associated with Pickeringite | MgAl2(SO4)4 · 22H2O |
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.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 | Cyanochroite | K2Cu(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) | 10.8870% | 3,375 | 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:
Slightly soluble in cold water. Soluble in hot water with hydrolysis.
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 Goldichite
mindat.org URL:
https://www.mindat.org/min-1722.html
Please feel free to link to this page.
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References for Goldichite
Reference List:
Graeber, Edward J., Rosenzweig, Abraham (1971) The crystal structures of yavapaiite, KFe(SO4)2, and goldichite, KFe(SO4)2·4H2O. American Mineralogist, 56 (11-12) 1917-1933
Yang, Zhuming, Giester, Gerald (2018) Hydrogen bonding in goldichite, KFe(SO4)2⋅4H2O: structure refinement. Mineralogy and Petrology, 112 (1) 135-142 doi:10.1007/s00710-017-0524-0
Localities for Goldichite
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.
Argentina | |
| rruff.geo.arizona.edu (n.d.) +1 other reference |
Canada | |
| Schindler et al. (2012) |
Caribbean Netherlands | |
| Anthony et al. (2016) | |
Chile | |
| Samples analysed by Tony Kampf of LAC ... |
| Peter G. Seroka collection |
China | |
| Cai et al. (2009) |
Greece | |
| Rieck (n.d.) |
| Kolitsch et al. (2014) |
| Rieck (n.d.) | |
| Rieck (n.d.) |
Italy | |
| De Michele (1974) |
| Biagioni et al. (2019) +1 other reference |
Peru | |
| Roth et al. (2012) |
Portugal | |
| Flahaut et al. (2018, September) |
Russia | |
| maurice.strahlen.org (2004) |
USA | |
| Bullock (1981) |
| Rosenzweig et al. (1955) +1 other reference |
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Javier Mine, Huac-huas District, Lucanas Province, Ayacucho, Peru