Witzkeite
A valid IMA mineral species
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About Witzkeite
Thomas Witzke
Formula:
Na4K4Ca(NO3)2(SO4)4 · 2H2O
Colour:
Colorless
Lustre:
Vitreous
Hardness:
2
Specific Gravity:
2.40
Crystal System:
Monoclinic
Name:
In honour of Dr. Thomas Witzke (b. 1963), German mineralogist, for his work on new, mainly secondary, mineral species. He has authored/coauthored descriptions of 18 new minerals as of 2021.
Type Locality:
This page provides mineralogical data about Witzkeite.
Unique Identifiers
Mindat ID:
42408
Long-form identifier:
mindat:1:1:42408:4
IMA Classification of Witzkeite
Approved
IMA Formula:
Na4K4Ca(NO3)2(SO4)4 · 2H2O
Approval year:
2011
First published:
2012
Type description reference:
Classification of Witzkeite
7.DG.60
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
D : Sulfates (selenates, etc.) with additional anions, with H2O
G : With large and medium-sized cations; with NO3, CO3, B(OH)4, SiO4 or IO3
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
D : Sulfates (selenates, etc.) with additional anions, with H2O
G : With large and medium-sized cations; with NO3, CO3, B(OH)4, SiO4 or IO3
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 |
|---|---|---|
| Wzk | 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 Witzkeite
Vitreous
Transparency:
Transparent
Colour:
Colorless
Streak:
White
Hardness:
2 on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
on {001}.
on {001}.
Parting:
None
Fracture:
Irregular/Uneven
Density:
2.40(2) g/cm3 (Measured) 2.403 g/cm3 (Calculated)
Optical Data of Witzkeite
Type:
Biaxial (-)
RI values:
nα = 1.470(5) nβ = 1.495(5) nγ = 1.510(5)
2V:
Measured: 50° to 70°, Calculated: 74°
Max. Birefringence:
δ = 0.040
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:
Weak.
Optical Extinction:
X = b; Y ~ a; Z = c.
Chemistry of Witzkeite
Mindat Formula:
Na4K4Ca(NO3)2(SO4)4 · 2H2O
Element Weights:
Crystallography of Witzkeite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/b
Setting:
C2/c
Cell Parameters:
a = 24.902(2) Å, b = 5.3323(4) Å, c = 17.246(1) Å
β = 94.281(7)°
β = 94.281(7)°
Ratio:
a:b:c = 4.67 : 1 : 3.234
Unit Cell V:
2283.6 ų
Z:
4
Morphology:
Tabular crystals up to 140 μm in length.
Twinning:
Twinning not observed.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 12.377 Å | (100) |
| 4.134 Å | (19) |
| 3.100 Å | (24) |
| 2.989 Å | (7) |
| 2.851 Å | (6) |
| 2.689 Å | (9) |
| 2.482 Å | (12) |
| 2.068 Å | (54) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47b : [Sulfates and sulfites] | |
| 47c : [Carbonates, phosphates, borates, nitrates] | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 52 : Guano- and urine-derived minerals | <0.4 |
Type Occurrence of Witzkeite
General Appearance of Type Material:
Tabular crystals up to 140 μm in length
Place of Conservation of Type Material:
Type material is deposited in the collections of the Mineralogical Museum of the University of Padova, Padova, Italy, catalogue number MMP M10009.
Geological Setting of Type Material:
The oxidation zone of a guano mining field
Associated Minerals at Type Locality:
Synonyms of Witzkeite
Other Language Names for Witzkeite
Related Minerals - Strunz-mindat Grouping
| 7.DG. | Mathesiusite | K5(UO2)4(SO4)4(VO5) · 4H2O |
| 7.DG.05 | Darapskite | Na3(SO4)(NO3) · H2O |
| 7.DG.10 | Clinoungemachite | (Na, K, Fe, SO4) |
| 7.DG.10 | Humberstonite | Na7K3Mg2(SO4)6(NO3)2 · 6H2O |
| 7.DG.10 | Ungemachite | K3Na8Fe(SO4)6(NO3)2 · 6H2O |
| 7.DG.15 | Chiyokoite | Ca3Si(CO3)[B(OH)4]O (OH)5 · 12H2O |
| 7.DG.15 | Kottenheimite | Ca 3Si(SO4)2(OH)6 · 12H2O |
| 7.DG.15 | Hielscherite | Ca3Si(SO4)(SO3)(OH)6 · 11H2O |
| 7.DG.15 | Jouravskite | Ca3Mn4+(SO4)(CO3)(OH)6 · 12H2O |
| 7.DG.15 | Thaumasite | Ca3(SO4)[Si(OH)6](CO3) · 12H2O |
| 7.DG.15 | Bentorite | Ca6Cr2(SO4)3(OH)12 · 26H2O |
| 7.DG.15 | Carraraite | Ca3(SO4)[Ge(OH)6](CO3) · 12H2O |
| 7.DG.15 | Ettringite | Ca6Al2(SO4)3(OH)12 · 26H2O |
| 7.DG.15 | Birunite | Ca18(SiO3)8.5(CO3)8.5SO4 · 15H2O(?) |
| 7.DG.15 | Siwaqaite | Ca6Al2(CrO4)3(OH)12 · 26H2O |
| 7.DG.15 | Buryatite | Ca3(Si,Fe3+,Al)(SO4)B(OH)4(OH,O)6 · 12H2O |
| 7.DG.15 | Charlesite | Ca6(Al,Si)2(SO4)2[B(OH)4](OH,O)12 · 26H2O |
| 7.DG.15 | Tatarinovite | Ca3Al(SO4)[B(OH)4](OH)6 · 12H2O |
| 7.DG.15 | Imayoshiite | Ca3Al(CO3)[B(OH)4](OH)6 · 12H2O |
| 7.DG.15 | Sturmanite | Ca6Fe3+2(SO4)2.5[B(OH)4](OH)12 · 25H2O |
| 7.DG.20 | Rapidcreekite | Ca2(SO4)(CO3) · 4H2O |
| 7.DG.25 | Tatarskite | Ca6Mg2(SO4)2(CO3)2(OH)4Cl4 · 7H2O |
| 7.DG.30 | Nakauriite | Cu8(SO4)4(CO3)(OH)6 · 48H2O |
| 7.DG.35 | Chessexite | (Na,K)4Ca2(Mg,Zn)3Al8(SO4)10(SiO4)2 · 40H2O |
| 7.DG.40 | Fuenzalidaite | K6(Na,K)4Na6Mg10(SO4)12(IO3)12 · 12H2O |
| 7.DG.40 | Carlosruizite | K6(Na,K)4Na6Mg10(SeO4)12(IO3)12 · 12H2O |
| 7.DG.45 | 'Chelyabinskite' | (Ca,Mg)3(SO4,CO3)2[Si(OH)6] · 9H2O (?) |
| 7.DG.55 | Ramazzoite | [Mg8Cu12(PO4)(CO3)4(OH)24(H2O)20][(H0.33SO4)3(H2O)36] |
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) | 18.7810% | 5,822 | 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:
Dissolves in water (slowly at 20 °C and more rapidly at 50 °C).
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 Witzkeite
mindat.org URL:
https://www.mindat.org/min-42408.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Witzkeite
Reference List:
Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2012) New minerals and nomenclature modifications approved in 2012. CNMNC Newsletter No 12. Mineralogical Magazine, 76 (1) 151-155 doi:10.1180/minmag.2012.076.1.151
Localities for Witzkeite
Showing 1 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.
Chile (TL) | |
| Nestola et al. (2012) |
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Punta de Lobos, Iquique, Iquique Province, Tarapacá, Chile