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Struvite-(K)
A valid IMA mineral species
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About Struvite-(K)
Heinrich C. G. Struve
Formula:
KMg(PO4) · 6H2O
Colour:
Colourless
Lustre:
Vitreous
Specific Gravity:
1.864 (Calculated)
Crystal System:
Orthorhombic
Member of:
Name:
Named for being the potassium analogue of Struvite. Struvite was named after Heinrich Christoph Gottfried Struve (10 January 1772, Regensburg, Germany - 9 January 1851, Hamburg, Germany) of the Russian diplomatic service, Consul at Hamburg (Germany). He was a co-founder of a natural science museum in Hamburg.
[For comment on name see http://www.mindat.org/mesg-7-284821.html]
[For comment on name see http://www.mindat.org/mesg-7-284821.html]
Co-Type Localities:
Isostructural with:
Unique Identifiers
Mindat ID:
27534
Long-form identifier:
mindat:1:1:27534:5
Similar Names
| Starovaite | A valid IMA mineral species | KCu5O(VO4)3 |
| Struvite | A valid IMA mineral species - grandfathered | (NH4)Mg(PO4) · 6H2O |
IMA Classification of Struvite-(K)
Classification of Struvite-(K)
8.CH.40
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
H : With large and medium-sized cations, RO4:H2O < 1:1
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
H : With large and medium-sized cations, RO4:H2O < 1:1
40.1.1.2
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
1 : AB(XO4)·xH2O
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
1 : AB(XO4)·xH2O
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 |
|---|---|---|
| Suv-K | 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 Struvite-(K)
Vitreous
Transparency:
Transparent
Colour:
Colourless
Streak:
White
Hardness Data:
Could not be measured
Cleavage:
None Observed
Fracture:
Conchoidal
Density:
1.864 g/cm3 (Calculated)
Optical Data of Struvite-(K)
Type:
Biaxial (+)
RI values:
nα = 1.490 nβ = 1.493 nγ = 1.493
Birefringence:
Small
Max. Birefringence:
δ = 0.003
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 (negative)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
No measured or calculated 2V is on file for this mineral, so the value used here (180°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
No measured or calculated 2V is on file for this mineral, so the value used here (180°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Dispersion:
Visible, r < v.
Comments:
The optic normal lying parallel to the needle axis, the mineral shows (±) elongation, depending on the position of the needles.
Chemistry of Struvite-(K)
Mindat Formula:
KMg(PO4) · 6H2O
Element Weights:
Crystallography of Struvite-(K)
Crystal System:
Orthorhombic
Class (H-M):
mm2 - Pyramidal
Space Group:
Pmn21
Cell Parameters:
a = 6.903 Å, b = 6.174 Å, c = 11.146 Å
Ratio:
a:b:c = 1.118 : 1 : 1.805
Unit Cell V:
475.03 ų (Calculated from Unit Cell)
Morphology:
Needles, elongated parallel to [100]. Forms include {001}, {010}, {101}, {012}, {110}, {111}, {012}.
Twinning:
Contact twins on (101) common.
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
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
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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
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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) |
|---|---|---|---|---|---|---|---|
| 0007262 | Struvite-(K) | Graeser S, Postl W, Bojar H P, Berlepsch P, Armbruster T, Raber T, Ettinger K, Walter F (2008) Struvite-(K), KMgPO4*6H2O, the potassium equivalent of struvite - a new mineral European Journal of Mineralogy 20 629-633 | 2008 | Lengenbach, Switzerland | 0 | 293 | |
| 0009654 | Struvite-(K) | Mathew M, Schroeder L W (1979) Crystal structure of a struvite analogue, MgKPO4*6H2O Acta Crystallographica B35 11-13 |  | 1979 | synthetic | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 4.26 Å | (100) |
| 4.14 Å | (80) |
| 3.27 Å | (90) |
| 2.905 Å | (50) |
| 2.699 Å | (50) |
| 2.650 Å | (70) |
| 1.954 Å | (50) |
Comments:
From type description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] |
Type Occurrence of Struvite-(K)
Co-Type Localities:
General Appearance of Type Material:
Extremely fine needles up to 0.5–0.7 mm in length and 20–30 μm across (Lengenbach). Pseudomorphosed aggregates, intergrown with newberyite, reaching up to several millimetres (Austria).
Place of Conservation of Type Material:
Natural History Museum, Basel, Switzerland, S17.
Geological Setting of Type Material:
With sulphosalts in dolomitic rock (Lengenbach) and with Pb-mineralisation in sericite-schist (Austria).
Associated Minerals at Type Locality:
Synonyms of Struvite-(K)
Other Language Names for Struvite-(K)
Relationship of Struvite-(K) to other Species
Member of:
Other Members of Struvite Group:
Common Associates
Associations Based on Photo Data:
| 1 photo of Struvite-(K) associated with Hentschelite | CuFe3+2(PO4)2(OH)2 |
Related Minerals - Strunz-mindat Grouping
| 8.CH. | Georgeliuite | Ca2Mn3+3O2(AsO4)3(H2O)2 · H2O |
| 8.CH.05 | Natrowalentaite | [Fe3+0.5Na0.5(H2O)6][NaAs3+2(Fe3+2.33W6+0.67)(PO4)2O7] |
| 8.CH.05 | Walentaite | [Mn2+(H2O)6][◻As3+3Fe3+3(PO4)2O7] |
| 8.CH.05 | Halilsarpite | [Mg(H2O)6][CaAs3+2(Fe3+2.67Mo6+0.33)(AsO4)2O7] |
| 8.CH.10 | Anapaite | Ca2Fe2+(PO4)2 · 4H2O |
| 8.CH.15 | Picropharmacolite | Ca4Mg(AsO4)2(HAsO4)2 · 11H2O |
| 8.CH.20 | Dittmarite | (NH4)Mg(PO4) · H2O |
| 8.CH.20 | Niahite | (NH4)Mn2+(PO4) · H2O |
| 8.CH.25 | Taranakite | K3Al5(PO3OH)6(PO4)2 · 18H2O |
| 8.CH.25 | Francoanellite | K3Al5(PO3OH)6(PO4)2 · 12H2O |
| 8.CH.25 | Macivorite | (NH4)3Al5(PO3OH)6(PO4)2 · 18H2O |
| 8.CH.30 | Schertelite | (NH4)2MgH2(PO4)2 · 4H2O |
| 8.CH.35 | Hannayite | (NH4)2Mg3H4(PO4)4 · 8H2O |
| 8.CH.40 | Hazenite | KNaMg2(PO4)2 · 14H2O |
| 8.CH.40 | Struvite | (NH4)Mg(PO4) · 6H2O |
| 8.CH.45 | Rimkorolgite | (Mg,Mn)5(Ba,Sr,Ca)(PO4)4 · 8H2O |
| 8.CH.50 | Bakhchisaraitsevite | Na2Mg5(PO4)4 · 7H2O |
| 8.CH.55 | Smolyaninovite | Co3Fe3+2(AsO4)4 · 11H2O |
| 8.CH.55 | Fahleite | CaZn5Fe3+2(AsO4)6 · 14H2O |
| 8.CH.60 | Barahonaite-(Fe) | (Ca,Cu,Na,Fe3+,Al)12Fe3+2(AsO4)8(OH,Cl)x · nH2O |
| 8.CH.60 | Barahonaite-(Al) | (Ca,Cu,Na,Fe3+,Al)12Al2(AsO4)8(OH,Cl)x · nH2O |
| 8.CH.70 | Epifanovite | NaCaCu5(PO4)4[AsO2(OH)2] · 7H2O |
| 8.CH.75 | Esdanaite-(Ce) | NaMnCe(PO4)2 · 4H2O |
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) | 14.6729% | 4,549 | 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
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 Struvite-(K)
mindat.org URL:
https://www.mindat.org/min-27534.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Struvite-(K)
Reference List:
Localities for Struvite-(K)
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.
Australia | |
| Peter Elliott unpub. Data |
Austria (TL) | |
| Postl et al. (2000) +2 other references |
Switzerland (TL) | |
| Roth (2007) +1 other reference |
Quick NavTopAbout Struvite-(K)Unique IdentifiersSimilar NamesIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesRelationshipsCommon AssociatesStrunz-MindatRadioactivityOther InformationInternet Links References Localities Locality List
Roßblei Mine, Eschach Alp, Obertalbach valley, Schladming, Liezen District, Styria, Austria