Kruijenite
A valid IMA mineral species
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About Kruijenite
Fred Kruijen
Formula:
Ca4Al4(SO4)F2(OH)16 · 2H2O
Colour:
Pale greenish-yellow to colourless
Hardness:
3
Specific Gravity:
2.573 (Calculated)
Crystal System:
Tetragonal
Name:
The mineral is named in honor of the Dutch collector of Eifel minerals Fred Kruijen (born in 1956). He has authored numerous articles in popular scientific periodicals and is a accomplished micro-mineral photographer. The name is pronounced "kru:yenait".
Unique Identifiers
Mindat ID:
53154
Long-form identifier:
mindat:1:1:53154:2
IMA Classification of Kruijenite
Approved
IMA Formula:
Ca4Al4(S6+O4)F2(OH)16·2H2O
Approval year:
2018
First published:
2019
Type description reference:
Chukanov, Nikita V., Zubkova, Natalia V., Blass, Günter, Pekov, Igor V., Varlamov, Dmitry A., Belakovskiy, Dmitriy I., Ksenofontov, Dmitry A., Britvin, Sergey N., Pushcharovsky, Dmitry Yu. (2019) Kruijenite, Ca4Al4(SO4)F2(OH)16·2H2O, a new mineral with microporous structure from the Eifel paleovolcanic region, Germany. Mineralogy and Petrology, 113 (2) 229-236 doi:10.1007/s00710-019-00653-3
Classification of Kruijenite
3.CG.30
3 : HALIDES
C : Complex halides
G : Aluminofluorides with CO3, SO4, PO4
3 : HALIDES
C : Complex halides
G : Aluminofluorides with CO3, SO4, PO4
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 |
|---|---|---|
| Kje | 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 Kruijenite
Colour:
Pale greenish-yellow to colourless
Streak:
White
Hardness:
3 on Mohs scale
Tenacity:
Brittle
Cleavage:
None Observed
Density:
2.573 g/cm3 (Calculated)
Optical Data of Kruijenite
Type:
Uniaxial (-)
RI values:
nω = 1.576(3) nε = 1.561(3)
Max. Birefringence:
δ = 0.015
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 (positive)
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 uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Pleochroism:
Non-pleochroic
Chemistry of Kruijenite
Mindat Formula:
Ca4Al4(SO4)F2(OH)16 · 2H2O
Element Weights:
Crystallography of Kruijenite
Crystal System:
Tetragonal
Class (H-M):
4/mmm(4/m2/m2/m) - Ditetragonal Dipyramidal
Space Group:
P4/nnc
Cell Parameters:
a = 12.9299(4) Å, c = 5.2791(3) Å
Ratio:
a:c = 1 : 0.408
Unit Cell V:
882.57 ų
Z:
2
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 9.12 Å | (77) |
| 4.565 Å | (100) |
| 4.084 Å | (50) |
| 2.964 Å | (74) |
| 2.694 Å | (27) |
| 2.321 Å | (24) |
| 2.284 Å | (29) |
| 1.971 Å | (40) |
Reference:
Chukanov, Nikita V., Zubkova, Natalia V., Blass, Günter, Pekov, Igor V., Varlamov, Dmitry A., Belakovskiy, Dmitriy I., Ksenofontov, Dmitry A., Britvin, Sergey N., Pushcharovsky, Dmitry Yu. (2019) Kruijenite, Ca4Al4(SO4)F2(OH)16·2H2O, a new mineral with microporous structure from the Eifel paleovolcanic region, Germany. Mineralogy and Petrology, 113 (2) 229-236 doi:10.1007/s00710-019-00653-3
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] |
Type Occurrence of Kruijenite
General Appearance of Type Material:
long prismatic tetragonal crystals up to 0.1 mm × 1 mm in cavities typically combined in radiating or random aggregates
Place of Conservation of Type Material:
collections of the Fersman Mineralogical Museum, Russian Academy of Sciences, Leninskiy Prospekt 18-2, Moscow 119071, Russia, registration number 5233/1
Geological Setting of Type Material:
calcic xenolith from tephra
Associated Minerals at Type Locality:
Reference:
Chukanov, Nikita V., Zubkova, Natalia V., Blass, Günter, Pekov, Igor V., Varlamov, Dmitry A., Belakovskiy, Dmitriy I., Ksenofontov, Dmitry A., Britvin, Sergey N., Pushcharovsky, Dmitry Yu. (2019) Kruijenite, Ca4Al4(SO4)F2(OH)16·2H2O, a new mineral with microporous structure from the Eifel paleovolcanic region, Germany. Mineralogy and Petrology, 113 (2) 229-236 doi:10.1007/s00710-019-00653-3
Synonyms of Kruijenite
Other Language Names for Kruijenite
Dutch:Kruijeniet
German:Kruijenit
Common Associates
Associations Based on Photo Data:
| 5 photos of Kruijenite associated with Ettringite | Ca6Al2(SO4)3(OH)12 · 26H2O |
| 2 photos of Kruijenite associated with Calcite | CaCO3 |
| 1 photo of Kruijenite associated with Thaumasite | Ca3(SO4)[Si(OH)6](CO3) · 12H2O |
| 1 photo of Kruijenite associated with Sharyginite | Ca3TiFe2O8 |
Related Minerals - Strunz-mindat Grouping
| 3.CG.3.CG. | Chukhrovite-(Ca) | Ca3Ca1.5Al2(SO4)F13 · 12H2O |
| 3.CG.05 | Stenonite | Sr2Al(CO3)F5 |
| 3.CG.10 | Meniaylovite | Ca4[(SO4)(SiF6)(AlF6)]F · 12H2O |
| 3.CG.10 | Chukhrovite-(Ce) | Ca3CeAl2(SO4)F13 · 12H2O |
| 3.CG.10 | Chukhrovite-(Y) | Ca3YAl2(SO4)F13 · 12H2O |
| 3.CG.10 | Chukhrovite-(Nd) | Ca3NdAl2(SO4)F13 · 12H2O |
| 3.CG.15 | Creedite | Ca3Al2(SO4)(OH)2F8 · 2H2O |
| 3.CG.20 | Bøggildite | Na2Sr2Al2PO4F9 |
| 3.CG.25 | Thermessaite-(NH4) | (NH4)2AlF3(SO4) |
| 3.CG.25 | Thermessaite | K2AlF3(SO4) |
Fluorescence of Kruijenite
Not fluorescent with UV excitation
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 Kruijenite
mindat.org URL:
https://www.mindat.org/min-53154.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
Mineral Dealers:
References for Kruijenite
Reference List:
Hålenius, U., Hatert, F., Pasero, M., Mills, S. J. (2018) CNMNC Newsletter 45, New minerals and nomenclature modifications approved in 2018. Mineralogical Magazine, 82 (5) 1225-1232 doi:10.1180/mgm.2018.160p.1229
Chukanov, Nikita V., Zubkova, Natalia V., Blass, Günter, Pekov, Igor V., Varlamov, Dmitry A., Belakovskiy, Dmitriy I., Ksenofontov, Dmitry A., Britvin, Sergey N., Pushcharovsky, Dmitry Yu. (2019) Kruijenite, Ca4Al4(SO4)F2(OH)16·2H2O, a new mineral with microporous structure from the Eifel paleovolcanic region, Germany. Mineralogy and Petrology, 113 (2) 229-236 doi:10.1007/s00710-019-00653-3
Localities for Kruijenite
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.
Germany (TL) | |
| Chukanov et al. (2019) |
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Feuerberg, Hohenfels-Essingen, Gerolstein, Vulkaneifel, Rhineland-Palatinate, Germany