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Kayrobertsonite

A valid IMA mineral species
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01399110017711020747052.jpg
Kayrobertsonite

Foote Lithium Co. Mine, Kings Mountain, Cleveland County, North Carolina, USA
09272640017701977708821.jpg
Kayrobertsonite, etc.

Silbergrube, Waidhaus, Neustadt an der Waldnaab District, Upper Palatinate, Bavaria, Germany
04880420017711019579090.jpg
Kayrobertsonite

Foote Lithium Co. Mine, Kings Mountain, Cleveland County, North Carolina, USA
07131290017362371527677.jpg
Kayrobertsonite

Foote Lithium Co. Mine, Kings Mountain, Cleveland County, North Carolina, USA
03120450017868293552306.jpg
Kayrobertsonite, etc.

Silbergrube, Waidhaus, Neustadt an der Waldnaab District, Upper Palatinate, Bavaria, Germany
01006730017362371514293.jpg
Kayrobertsonite

Foote Lithium Co. Mine, Kings Mountain, Cleveland County, North Carolina, USA
01399110017711020747052.jpg
Kayrobertsonite

Foote Lithium Co. Mine, Kings Mountain, Cleveland County, North Carolina, USA
09272640017701977708821.jpg
Kayrobertsonite, etc.

Silbergrube, Waidhaus, Neustadt an der Waldnaab District, Upper Palatinate, Bavaria, Germany
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About KayrobertsoniteHide

05494250017272472564056.jpg
Kay Robertson with Dr. Rob Lavinsky
Formula:
[MnAl2(PO4)2(OH)2(H2O)4] · 2H2O
Colour:
Snow-white
Crystal System:
Triclinic
Name:
Named in honor of Kay Robertson (born Gabriella Katherine Loewi) (b. 23 April 1920, Venice, Italy - d. March 23, 2020, Puget Sound area) of Los Angeles, California, USA, a well known collector, especially of German localities, since the 1950s. She was a founding member of the Southern California Micromineralogists Society.
The OH analogue of nordgauite. Structural topology similar to that of nordgauite, but with double amount of water molecules in the [001] channels.


Unique IdentifiersHide

Mindat ID:
46697
Long-form identifier:
mindat:1:1:46697:4

IMA Classification of KayrobertsoniteHide

Classification of KayrobertsoniteHide

Strunz-mindat (2026):
8.DC.30

8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
C : With only medium-sized cations, (OH, etc.):RO4 = 1:1 and < 2:1

Mineral SymbolsHide

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

SymbolSourceReference for Standard
KayIMA–CNMNCWarr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43

Physical Properties of KayrobertsoniteHide

Colour:
Snow-white

Optical Data of KayrobertsoniteHide

Type:
Biaxial (-)
RI values:
nα = 1.530(1) nβ = 1.554(1) nγ = 1.566(1)
2V:
Measured: 70.3° (5), Calculated: 69.6°
Max. Birefringence:
δ = 0.036
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.

Surface Relief:
Low (positive)
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.
Pleochroism:
Non-pleochroic

Chemistry of KayrobertsoniteHide

Mindat Formula:
[MnAl2(PO4)2(OH)2(H2O)4] · 2H2O
Element Weights:
Element% weight
O58.054 %
P14.049 %
Mn12.459 %
Al12.238 %
H3.200 %

Calculated from ideal end-member formula.
O
P
Mn
Al
H
Elements listed:
Al, H, Mn, O, P - search for minerals with similar chemistry

Crystallography of KayrobertsoniteHide

Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Setting:
P1
Cell Parameters:
a = 10.049(2) Å, b = 10.205(2) Å, c = 6.083(1) Å
α = 91.79(3)°, β = 99.70(3)°, γ = 98.02(3)°
Ratio:
a:b:c = 0.985 : 1 : 0.596
Unit Cell V:
607.9 ų
Z:
2
Morphology:
Intergrown masses offibrous needles up to 100 μm long and less than 5 μm wide

X-Ray Powder DiffractionHide

Powder Diffraction Data:
d-spacingIntensity
10.047 Å(100)
9.804 Å(8)
7.629 Å(44)
5.029 Å(12)
4.695 Å(10)
3.023 Å(12)
2.952 Å(10)
2.579 Å(10)

Geological EnvironmentHide

Paragenetic Mode(s):
Paragenetic ModeEarliest Age (Ga)
Stage 4b: Highly evolved igneous rocks>3.0
34 : Complex granite pegmatites
Stage 7: Great Oxidation Event<2.4
47a : [Near-surface hydration of prior minerals]
47c : [Carbonates, phosphates, borates, nitrates]
47e : [Vanadates, chromates, manganates]

Type Occurrence of KayrobertsoniteHide

Co-Type Localities:
ⓘ Hagendorf South Pegmatite, Hagendorf, Waidhaus, Neustadt an der Waldnaab District, Upper Palatinate, Bavaria, Germany
ⓘ Foote Lithium Co. Mine, Kings Mountain, Cleveland County, North Carolina, USA
General Appearance of Type Material:
intergrown masses of snow-white, soft, finely fibrous needles, less than 5 μm in diameter and no more than 100 μm in length
Place of Conservation of Type Material:
Co-type material is deposited in the mineralogical collections of the Museum Victoria, Melbourne, Victoria, Australia, registered numbers M53379, M53380 and M48795, and the Natural History Museum of Los Angeles County, Los Angeles, CA 90007, USA, registr
Geological Setting of Type Material:
pegmatites
Reference:
Mills, Stuart J., Grey, Ian E., Kampf, Anthony R., Birch, William D., MaCrae, Colin M., Smith, Jason B., Keck, Erich (2016) Kayrobertsonite, MnAl2(PO4)2(OH)2·6H2O, a new phosphate mineral related to nordgauite. European Journal of Mineralogy, 28 (3) 649-654 doi:10.1127/ejm/2016/0028-2524

Synonyms of KayrobertsoniteHide

Other Language Names for KayrobertsoniteHide

Common AssociatesHide

Associations Based on Photo Data:
3 photos of Kayrobertsonite associated with Kastningite(Mn2+,Fe2+,Mg)Al2(PO4)2(OH)2 · 8H2O
1 photo of Kayrobertsonite associated with Rittmannite{(Mn2+,Ca)}{Mn2+}{(Fe2+,Mn2+,Mg)2}{(Al,Fe3+)2}(PO4)4(OH)2 · 8H2O
1 photo of Kayrobertsonite associated with Jahnsite GroupXM1M22M32(H2O)8(OH)2(PO4)4
1 photo of Kayrobertsonite associated with ZwieseliteFe2+2(PO4)F
1 photo of Kayrobertsonite associated with StewartiteMn2+Fe3+2(PO4)2(OH)2 · 8H2O
1 photo of Kayrobertsonite associated with StrengiteFePO4 · 2H2O

Related Minerals - Strunz-mindat GroupingHide

8.DC.FerroberauniteFe2+Fe3+5(PO4)4(OH)5 · 6H2OMon. 2/m : B2/b
8.DC.CésarferreiraiteFe2+ Fe3+2(AsO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.FerrivauxiteFe3+Al2(PO4)2(OH)3 · 5H2OTric. 1 : P1
8.DC.IanbruceiteZn2(AsO4)(OH) · 3H2OMon. 2/m : P21/b
8.DC.05NissoniteCu2Mg2(PO4)2(OH)2 · 5H2OMon. 2/m : B2/b
8.DC.07EuchroiteCu2(AsO4)(OH) · 3H2OOrth. 222 : P212121
8.DC.10LegranditeZn2(AsO4)(OH) · H2OMon. 2/m : P21/b
8.DC.12StrashimiriteCu8(AsO4)4(OH)4 · 5H2OMon.
8.DC.15EarlshannoniteMn2+Fe3+2(PO4)2(OH)2 · 4H2OMon. 2/m : P21/b
8.DC.15KunatiteCuFe3+2(PO4)2(OH)2 · 4H2OMon. 2/m : P21/b
8.DC.15'UM2006-27-PO:FeHZn'ZnFe3+2(PO4)2(OH)2 · 4H2OMon.
8.DC.15'UKI-2006-(PO:AlCuFeH)'Fe2+Al3+2(PO4)2(OH)2 · 4H2O
8.DC.15CobaltarthuriteCoFe3+2(AsO4)2(OH)2 · 4H2OMon. 2/m : P21/b
8.DC.15ArthuriteCuFe3+2(AsO4)2(OH)2 · 4H2OMon. 2/m : P21/b
8.DC.15OjuelaiteZnFe3+2(AsO4)2(OH)2 · 4H2OMon. 2/m : P21/b
8.DC.15WhitmoreiteFe2+Fe3+2(PO4)2(OH)2 · 4H2OMon. 2/m : P21/b
8.DC.15BendadaiteFe2+Fe3+2(AsO4)2(OH)2 · 4H2OMon. 2/m : P21/b
8.DC.17KleemaniteZnAl2(PO4)2(OH)2 · 3H2OMon.
8.DC.20MagnesiobermaniteMgMn3+2(PO4)2(OH)2 · 4H2OMon. 2 : P21
8.DC.20BermaniteMn2+Mn3+2(PO4)2(OH)2 · 4H2OMon. 2/m : P2/b
8.DC.20CoralloiteMn2+Mn3+2(AsO4)2(OH)2 · 4H2OTric. 1 : P1
8.DC.22KovdorskiteMg2(PO4)(OH) · 3H2OMon. 2/m : P21/b
8.DC.25ZincostrunziteZnFe3+2(PO4)2(OH)2 · 6.5H2OTric. 1 : P1
8.DC.25MetavauxiteFe2+Al2(PO4)2(OH)2 · 8H2OMon. 2/m : P21/b
8.DC.25MetavivianiteFe2+Fe3+2(PO4)2(OH)2 · 6H2OTric. 1 : P1
8.DC.25FerristrunziteFe3+Fe3+2(PO4)2(OH)3 · 5H2OTric.
8.DC.25StrunziteMn2+Fe3+2(PO4)2(OH)2 · 6H2OTric. 1 : P1
8.DC.25FerrostrunziteFe2+Fe3+2(PO4)2(OH)2 · 6H2OTric.
8.DC.27BerauniteFe3+6(PO4)4O(OH)4 · 6H2OMon. m : Bb
8.DC.27TvrdýiteFe2+Fe3+2Al3(PO4)4(OH)5(H2O)4 · 2H2OMon. 2/m : B2/b
8.DC.27ZincoberauniteZnFe3+5(PO4)4(OH)5 · 6H2OMon. 2/m : B2/b
8.DC.30MaghrebiteMgAl2(AsO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.30FerrolaueiteFe2+Fe3+2(PO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.30UshkoviteMgFe3+2(PO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.30LaueiteMn2+Fe3+2(PO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.30ParavauxiteFe2+Al2(PO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.30SigloiteFe3+Al2(PO4)2(OH)3 · 7H2OTric. 1 : P1
8.DC.30NordgauiteMnAl2(PO4)2(F,OH)2 · 5H2OTric. 1 : P1
8.DC.30KummeriteMn2+Fe3+Al(PO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.30MangangordoniteMn2+Al2(PO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.30StewartiteMn2+Fe3+2(PO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.30GordoniteMgAl2(PO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.30Kastningite(Mn2+,Fe2+,Mg)Al2(PO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.30PseudolaueiteMn2+Fe3+2(PO4)2(OH)2 · 8H2OMon. 2/m : P21/b
8.DC.32KamarizaiteFe3+3(AsO4)2(OH)3 · 3H2OTric. 1 : P1
8.DC.32TinticiteFe3+3(PO4)2(OH)3 · 3H2OTric. 1 : P1
8.DC.35VauxiteFe2+Al2(PO4)2(OH)2 · 6H2OTric. 1 : P1
8.DC.37VantasseliteAl4(PO4)3(OH)3 · 9H2OOrth.
8.DC.40CacoxeniteFe3+24AlO6(PO4)17(OH)12 · 75H2OHex. 6/m : P63/m
8.DC.45SouzaliteMg3Al4(PO4)4(OH)6 · 2H2OTric. 1
8.DC.45Gormanite(Fe2+,Mg)3(Al,Fe3+)4(PO4)4(OH)6 · 2H2OTric.
8.DC.47KingiteAl3(PO4)2F2(OH) · 7H2OTric.
8.DC.50AllanpringiteFe3+3(PO4)2(OH)3 · 5H2OMon. 2/m : P21/m
8.DC.50FluorwavelliteAl3(PO4)2(OH)2F · 5H2OOrth. mmm(2/m2/m2/m)
8.DC.50WavelliteAl3(PO4)2(OH)3 · 5H2OOrth. mmm(2/m2/m2/m)
8.DC.52KribergiteAl5(PO4)3(SO4)(OH)4 · 4H2OTric. 1 : P1
8.DC.55MapimiteZn2Fe3+3(AsO4)3(OH)4 · 10H2OMon. m : Bm
8.DC.57OgdensburgiteCa2Fe3+4(Zn,Mn2+)(AsO4)4(OH)6 · 6H2OOrth. mmm(2/m2/m2/m) : Cmmm
8.DC.60CloncurryiteCu0.5(VO)0.5Al2(PO4)2F2 · 5H2OMon. 2/m : P21/b
8.DC.60Nevadaite(Cu2+,Al,V3+)6Al8(PO4)8F8(OH)2 · 22H2OOrth. mmm(2/m2/m2/m)
8.DC.62KenngottiteMn2+3Fe3+4(PO4)4(OH)6(H2O)2 Mon. 2/m : P2/b
8.DC.67MolinelloiteCu(H2O)(OH)V4+O(V5+O4)Tric. 1 : P1
8.DC.70WhitecapsiteH16Fe2+5Fe3+14Sb3+6(AsO4)18O16 · 120H2OHex. 6/m : P63/m
8.DC.75HeimitePbCu2(AsO4)(OH)3 · 2H2OMon. 2/m
8.DC.80LedneviteCu[PO3(OH)] · H2OMon. 2/m : P21/b

Other InformationHide

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 KayrobertsoniteHide

References for KayrobertsoniteHide

Localities for KayrobertsoniteHide

Showing 4 localities.

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
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Locality ListHide

- 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). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.
Germany
 
  • Bavaria
    • Lower Bavaria
      • Regen District
        • Zwiesel
          • Rabenstein
Grey et al. (2026)
    • Upper Palatinate
      • Neustadt an der Waldnaab District
        • Waidhaus
          • Hagendorf
Hålenius et al. (2015) +1 other reference
EDS Jason B. Smith
USA (TL)
 
  • North Carolina
    • Cleveland County
      • Kings Mountain
Hålenius et al. (2015) +2 other references
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