Andyrobertsite
A valid IMA mineral species
This page kindly sponsored by Nekkhi Murtishi
About Andyrobertsite
Andrew C. Roberts
Formula:
KCdCu5(AsO4)4(H2AsO4) · 2H2O
Colour:
Electric blue; greenish blue in transmitted light.
Lustre:
Vitreous
Hardness:
3
Specific Gravity:
4.011 (Calculated)
Crystal System:
Monoclinic
Name:
Named in honor of Andrew (Andy) Clifford Roberts (1950-), mineralogist with the Geological Survey of Canada, specialist in documentation of new mineral species, in particular from low-temperature secondary parageneses.
Isostructural with:
Unique Identifiers
Mindat ID:
6802
Long-form identifier:
mindat:1:1:6802:0
IMA Classification of Andyrobertsite
Approved
IMA Formula:
KCd2+Cu2+5(As5+O4)4[As5+(OH)2O2]·2H2O
Approval year:
1997
First published:
1999
Classification of Andyrobertsite
8.DH.50
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
H : With large and medium-sized cations, (OH, etc.):RO4 < 1:1
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
H : With large and medium-sized cations, (OH, etc.):RO4 < 1:1
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 |
|---|---|---|
| Arb | 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 Andyrobertsite
Vitreous
Transparency:
Transparent
Colour:
Electric blue; greenish blue in transmitted light.
Streak:
Pale blue
Hardness:
3 on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
Good on (100)
Good on (100)
Fracture:
Conchoidal
Density:
4.011 g/cm3 (Calculated)
Comment:
The calculated density for an aggregate crystal of andyrobertsite and calcioandyrobertsite in a 50:50 proportion of the end-members.
Optical Data of Andyrobertsite
Type:
Biaxial (-)
RI values:
nα = 1.720(3) nβ = 1.749(1) nγ = 1.757(1)
2V:
Measured: 50° (5), Calculated: 55°
Max. Birefringence:
δ = 0.037
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:
Very High (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 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.
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.
Dispersion:
relatively strong
Optical Extinction:
X ∧ a = 12° (in β obtuse); Y = b; Z = c.
Pleochroism:
Non-pleochroic
Chemistry of Andyrobertsite
Mindat Formula:
KCdCu5(AsO4)4(H2AsO4) · 2H2O
Element Weights:
Crystallography of Andyrobertsite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/m
Setting:
P21/m
Cell Parameters:
a = 9.8102(9) Å, b = 10.0424(6) Å, c = 9.9788(6) Å
β = 101.686(7)°
β = 101.686(7)°
Ratio:
a:b:c = 0.977 : 1 : 0.994
Unit Cell V:
962.71 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Platy habit with forms {100} (dominant), {210}, {001}, {102} and {011}.
Twinning:
No twinning observed.
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
Remove metal-metal sticks
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
Black Background | White Background
Perspective On | Perspective Off
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
Console Off | On | Grey | Yellow
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) |
|---|---|---|---|---|---|---|---|
| 0005686 | Andyrobertsite | Cooper M A, Hawthorne F C (2000) Highly undersaturated anions in the crystal structure of andyrobertsite - calcio-andyrobertsite, a doubly acid arsenate of the form K(Cd,Ca)[Cu5(AsO4)4{As(OH)2O2}](H2O)2 The Canadian Mineralogist 38 817-830 |  | 2000 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 9.64 Å | (100) |
| 3.145 Å | (50) |
| 4.46 Å | (40) |
| 3.048 Å | (40) |
| 2.698 Å | (40) |
| 7.00 Å | (30) |
| 4.81 Å | (30) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47d : [Arsenates, antimonates, selenates, bismuthinates] |
Type Occurrence of Andyrobertsite
General Appearance of Type Material:
Lamellar intergrowth with calcioandyrobertsite as plates, to 10 mm, that radiate from the center of an aggregate 1.4 cm long and 1 cm at the base.
Place of Conservation of Type Material:
Royal Ontario Museum, Toronto, Ontario, Canada (M47022 and M47110).
The Natural Museum of Natural History, Washington, D.C., USA (171487).
The Natural Museum of Natural History, Washington, D.C., USA (171487).
Associated Minerals at Type Locality:
Synonyms of Andyrobertsite
Other Language Names for Andyrobertsite
Dutch:Andyrobertsiet
French:Andyrobertsite
German:Andyrobertsit
Norwegian:Andyrobertsitt
Russian:Эндиробертсит
Spanish:Andyrobertsita
Relationship of Andyrobertsite to other Species
Structurally related to group(s):
| Lavendulan Group | Mahnertite, richelsdorfite, andyrobertsite and calcioandyrobertsite are structurally ... |
Common Associates
Associations Based on Photo Data:
| 4 photos of Andyrobertsite associated with Calcioandyrobertsite | KCaCu5(AsO4)4(H2AsO4) · 2H2O |
Related Minerals - Strunz-mindat Grouping
| 8.DH. | Thebaite-(NH4) | (NH4)3Al(C2O4)(PO3OH)2(H2O) |
| 8.DH. | Whiteite-(MnMnMn) | Mn2+Mn2+Mn2+2Al2(PO4)4(OH)2 · 8H2O |
| 8.DH. | Ammoniotinsleyite | (NH4)Al2(PO4)2(OH) · 2H2O |
| 8.DH. | Bergbauerite | (H2O)2Mn2(Fe2Ti)(PO4)4(OH)2(H2O)10 · 4H2O |
| 8.DH. | Dendoraite-(NH4) | (NH4)2NaAl(C2O4)(PO3OH)2(H2O)2 |
| 8.DH. | Rowleyite | [Na(NH4,K)9Cl4][V5+,4+2(P,As)O8]6 · n[H2O,Na,NH4,K,Cl] |
| 8.DH. | Hochleitnerite | Mn2Ti3(PO4)4O2(H2O)2 · 14H2O |
| 8.DH. | Whiteite-(CaMnFe) | CaMnFe2Al2(PO4)4(OH)2 · 8H2O |
| 8.DH.05 | Minyulite | KAl2(PO4)2F · 4H2O |
| 8.DH.10 | Leucophosphite | KFe3+2(PO4)2(OH) · 2H2O |
| 8.DH.10 | Tinsleyite | KAl2(PO4)2(OH) · 2H2O |
| 8.DH.10 | Spheniscidite | (NH4,K)(Fe3+,Al)2(PO4)2(OH) · 2H2O |
| 8.DH.15 | Jahnsite-(CaMnFe) | {Ca}{Mn2+}{Fe2+2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Jahnsite-(NaMnMn) | {Na}{Mn2+}{(Mn2+,Fe3+)2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Jahnsite-(CaMnMg) | {Ca}{Mn2+}{(Mg,Fe2+)2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Jahnsite-(CaMnMn) | {Ca}{Mn2+}{Mn2+2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Whiteite-(MnMnMg) | MnMnMg2Al2(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Jahnsite-(CaMnZn) | {Ca}{Mn2+}{Zn2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Jahnsite-(MnMnMg) | {Mn2+}{Mn2+}{Mg2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Jahnsite-(MnMnFe) | {Mn2+}{Mn2+}{Fe2+2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | 'Jahnsite-(CaFeFe)' | {Ca}{Fe2+}{Fe2+2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Rittmannite | {(Mn2+,Ca)}{Mn2+}{(Fe2+,Mn2+,Mg)2}{(Al,Fe3+)2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Keckite | CaMn2+(Fe3+Mn2+)Fe3+2(PO4)4(OH)3 · 7H2O |
| 8.DH.15 | Jahnsite-(NaMnMg) | {(Na,Ca)}{(Mn2+,Fe3+)}{(Mg,Fe3+)2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | 'Jahnsite-(CaMgMg)' | {Ca}{Mg}{Mg2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Jahnsite-(MnMnZn) | {Mn2+}{Mn2+}{Zn2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Whiteite-(CaMgMg) | CaMg3Al2(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Whiteite-(CaFeMg) | {Ca}{(Fe2+,Mn2+)}{Mg2}{Al2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Whiteite-(CaMnMg) | {Ca}{Mn2+}{Mg2}{Al2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Whiteite-(MnFeMg) | {(Mn2+,Ca)}{(Fe2+,Mn2+)}{Mg2}{Al2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Jahnsite-(MnMnMn) | {Mn2+}{Mn2+}{Mn2+2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | 'Kaluginite' | (Mn2+,Ca)MgFe3+(PO4)2(OH) · 4H2O |
| 8.DH.15 | Jahnsite-(CaFeMg) | {Ca}{Fe2+}{Mg2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Whiteite-(CaMnMn) | {Ca}{Mn2+}{Mn2}{Al2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Jahnsite-(NaFeMg) | {Na}{Fe3+}{Mg2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.20 | Segelerite | Ca2 Mg2 Fe3+2(PO4)4(OH)2 · 8H2O |
| 8.DH.20 | Lun'okite | (Mn,Ca)(Mg,Fe,Mn)Al(PO4)2OH · 4H2O |
| 8.DH.20 | Manganosegelerite | (Mn2+,Ca)(Mn2+,Fe2+,Mg)Fe3+(PO4)2(OH) · 4H2O |
| 8.DH.20 | Wilhelmvierlingite | CaMnFe3+(PO4)2(OH) · 2H2O |
| 8.DH.20 | Juonniite | CaMgSc(PO4)2(OH) · 4H2O |
| 8.DH.20 | Overite | CaMgAl(PO4)2(OH) · 4H2O |
| 8.DH.25 | Calcioferrite | Ca4MgFe3+4(PO4)6(OH)4 · 12H2O |
| 8.DH.25 | Zodacite | Ca4Mn2+Fe3+4(PO4)6(OH)4 · 12H2O |
| 8.DH.25 | Fanfaniite | Ca4Mn2+Al4(PO4)6(OH)4 · 12H2O |
| 8.DH.25 | Kingsmountite | Ca3Mn2+FeAl4(PO4)6(OH)4 · 12H2O |
| 8.DH.25 | Montgomeryite | Ca4MgAl4(PO4)6(OH)4 · 12H2O |
| 8.DH.30 | Pararobertsite | Ca2Mn3+3(PO4)3O2 · 3H2O |
| 8.DH.30 | Robertsite | Ca2Mn3+3(PO4)3O2 · 3H2O |
| 8.DH.30 | Arseniosiderite | Ca2Fe3+3(AsO4)3O2 · 3H2O |
| 8.DH.30 | Sailaufite | (Ca,Na,◻)2Mn3+3(AsO4)2(CO3)O2 · 3H2O |
| 8.DH.30 | Mitridatite | Ca2Fe3+3(PO4)3O2 · 3H2O |
| 8.DH.30 | Kolfanite | Ca2Fe3+3O2(AsO4)3 · 2H2O |
| 8.DH.35 | Mantienneite | KMg2Al2Ti(PO4)4(OH)3 · 15H2O |
| 8.DH.35 | Sperlingite | (H2O)K(Mn2+Fe3+)(Al2Ti)(PO4)4[O(OH)] [(H2O)9(OH)] · 4H2O |
| 8.DH.35 | Paulkerrite | K(Mg,Mn2+)2(Fe3+,Al,Ti,Mg)2Ti(PO4)4(OH)3 · 15H2O |
| 8.DH.35 | Hydroxylbenyacarite | (H2O)2Mn2(Ti2Fe)(PO4)4[O(OH)](H2O)10 · 4H2O |
| 8.DH.35 | Macraeite | K(H2O)Mn2(Fe2Ti)(PO4)4[O(OH)](H2O)10 · 4H2O |
| 8.DH.35 | Benyacarite | (H2O)2Mn2Ti2Fe3+(PO4)4(OF)(H2O)10 · 4H2O |
| 8.DH.35 | Fluormacraeite | [(H2O)K]Mn2(Fe2Ti)(PO4)4(OF)(H2O)10 · 4H2O |
| 8.DH.40 | Xanthoxenite | Ca4Fe3+2(PO4)4(OH)2 · 3H2O |
| 8.DH.45 | Mahnertite | NaCu3(AsO4)2Cl · 5H2O |
| 8.DH.50 | Calcioandyrobertsite | KCaCu5(AsO4)4(H2AsO4) · 2H2O |
| 8.DH.55 | Englishite | K3Na2Ca10Al15(PO4)21(OH)7 · 26H2O |
| 8.DH.60 | Bouazzerite | Bi6(Mg,Co)11Fe3+14(AsO4)18(OH)4O12 · 86H2O |
| 8.DH.65 | Galliskiite | Ca4Al2(PO4)2F8 · 5H2O |
| 8.DH.70 | Joteite | Ca2CuAl(AsO4)[AsO3(OH)]2(OH)2 · 5H2O |
| 8.DH.75 | Kampelite | Ba6Mg3Sc8(PO4)12(OH)6 · 7H2O |
| 8.DH.80 | Kapundaite | NaCaFe4(PO4)4(OH)3 · 5H2O |
| 8.DH.85 | Vaniniite | Ca2Mn2+3Mn3+2O2(AsO4)4 · 2H2O |
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) | 3.2531% | 1,008 | 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
Fluorescence of Andyrobertsite
Not fluorescent.
Other Information
IR Spectrum:
Broad IR absorption at ~3300 cm-1 and a sharp weaker absorption at 1644 cm-1, indicating the presence of H2O in the structure; a sharp absorption at 3448 cm-1 is compatible with the presence of OH in the structure.
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 Andyrobertsite
mindat.org URL:
https://www.mindat.org/min-6802.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 Andyrobertsite
Reference List:
Cooper, Mark A., Hawthorne, Frank C., Pinch, William W., Grice, Joel D. (1999) Andyrobertsite and Calcioandyrobertsite: Two New Minerals from the Tsumeb Mine, Tsumeb, Namibia. The Mineralogical Record, 30 (3) 181-186
Localities for Andyrobertsite
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.
Namibia (TL) | |
| Cooper et al. (1999) +1 other reference |
Quick NavTopAbout AndyrobertsiteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesRelationshipsCommon AssociatesStrunz-MindatRadioactivityFluorescence Other InformationInternet Links References Localities Locality List
Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia