Andyrobertsite Mineral Data

Andyrobertsite Mineral Data +

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General Andyrobertsite Information

Chemical Formula:

KCdCu5(AsO4)4[As(OH)2O2]·2(H2O)

Composition:

Molecular Weight = 1,201.88 gm

Potassium 3.25 % K 3.92 % K₂O

Cadmium 9.35 % Cd 10.68 % CdO

Copper 26.44 % Cu 33.09 % CuO

Arsenic 31.17 % As 47.81 % As₂O₅

Hydrogen 0.50 % H 4.50 % H₂O

Oxygen 29.29 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

KCdCu₅(AsO₄)₄(As(OH)2O2)·2(H₂O)

Environment:

Single specimen found at the mine. Forms a series with calcioandyrobertsite.

IMA Status:

Approved IMA 1999 (Dana # Added)

Locality:

Tsumeb Mine, Tsumeb, Namibia. Link to MinDat.org Location Data.

Name Origin:

Named after Andrew C. Roberts (1950-), mineralogist with the Geological Survey of Canada, specialist in documentation of new mineral species, in particular from low-temperature seco ndary parageneses.

Synonym:

ICSD 89894

IMA1997-023

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Andyrobertsite Crystallography

Axial Ratios:

a:b:c =0.9776:1:0.9941

Cell Dimensions:

a = 9.81, b = 10.034, c = 9.975, Z = 2; beta = 101.84° V = 960.98 Den(Calc)= 4.15

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/m

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 9.64(1), 3.145(0.5), 4.46(0.4),

Physical Properties of Andyrobertsite

Cleavage:

[100] Good

Color:

Electric blue.

Density:

4.011

Diaphaniety:

Transparent

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

Platy - Sheet forms (e.g. micas).

Hardness:

3 - Calcite

Luster:

Vitreous (Glassy)

Streak:

pale blue

Optical Properties of Andyrobertsite

Gladstone-Dale:

CI meas= -0.085 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.048 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1788,KPDmeas= 0.185,KC= 0.1706

Optical Data:

Biaxial (-), a=1.72, b=1.749, g=1.757, bire=0.0370

Calculated Properties of Andyrobertsite

Electron Density:

r_electron=3.86 gm/cc
note: r_{Andyrobertsite}=4.15 gm/cc.

Fermion Index

Fermion Index = 0.02355
Boson Index = 0.97645

Photoelectric:

PE_{Andyrobertsite}= 58.24 barns/electron
U=PE_{Andyrobertsite} x r_electron= 224.84 barns/cc.

Radioactivity:

GRapi = 43.68 (Gamma Ray American Petroleum Institute Units)

Estimated Radioactivity from Andyrobertsite - barely detectable

Andyrobertsite Classification

Dana Class:

42.9.2.3 (42)Hydrated Phosphates, etc., Containing Hydroxyl or Halogen

(42.9)where (A)3 (XO4)2 Zq · x(H2O)

(42.9.2)Dana Group

42.9.2.1 Souzalite (Mg,Fe)3(Al,Fe)4(PO4)4(OH)6·2(H2O) P1,P 1 Tri

42.9.2.2 Gormanite Fe3Al4(PO4)4(OH)6·2(H2O) P1,P 1 Tri

42.9.2.3 Andyrobertsite ! KCdCu5(AsO4)4[As(OH)2O2]·2(H2O) P 2₁/m 2/m

42.9.2.4 Calcio-andyrobertsite-1M! KCaCu5(AsO4)4[As(OH)2O2]·2(H2O) P 2₁/m 2/m

42.9.2.5 Calcio-andyrobertsite-2O! KCaCu5(AsO4)4[As(OH)2O2]·2(H2O) P nma 2/m 2/m 2/m

Strunz Class:

VII/D.25-35 VII - Phosphates, Arsenates and Vanadates

VII/D - Water-bearing phosphates with unfamiliar anions, cations of very big and medium size: Al, Mg and Ca, Na, K

VII/D.25 - Lavendulan series

VII/D.25-10 Sampleite NaCaCu5(PO4)4Cl·5(H2O) pseudo TET 2/m 2/m 2/m

VII/D.25-20 Lavendulan NaCaCu5(AsO4)4Cl·5(H2O) Unk Ortho

VII/D.25-22 Zinclavendulan* NaCa(Zn,Cu)5(AsO4)4Cl·4-5(H2O) Unk Ortho

VII/D.25-24 Lemanskiite! NaCaCu5(AsO4)4Cl·5(H2O) P 4₁22 or P 4₃22 Tetra

VII/D.25-25 Zdenekite NaPbCu5(AsO4)4Cl·5(H2O) P 4₁22,P 4₃22 4 2 2

VII/D.25-27 Mahnertite! (Na,Ca)Cu3(AsO4)2Cl·5(H2O) I 4mmm 4 2 2

VII/D.25-30 Shubnikovite Ca2Cu8(AsO4)6Cl(OH)·7(H2O)(?) Unk Ortho

VII/D.25-33 Goldquarryite! (Cu,[])(Cd,Ca)2Al3(PO4)4F2(H2O)10{(H2O,F)}2 P1 1

VII/D.25-35 Andyrobertsite KCdCu5(AsO4)4[As(OH)2O2]·2(H2O) P 2₁/m 2/m

VII/D.25-36 Calcio-andyrobertsite-1M! KCaCu5(AsO4)4[As(OH)2O2]·2(H2O) P 2₁/m 2/m

VII/D.25-36* Calcio-andyrobertsite-2O! KCaCu5(AsO4)4[As(OH)2O2]·2(H2O) P nma 2/m 2/m 2/m

VII/D.25-38 Esperanzaite! NaCa2Al2(AsO4)2F4(OH)·2(H2O) P 2₁/m 2/m

VII/D.25-40 Englishite K3Na2Ca10Al15(PO4)21(OH)7·26(H2O) A2 or Aa 2

Other Andyrobertsite Information

References:

NAME( MinRec, Vol 30) PHYS. PROP.(MinRec, Vol 30) OPTIC PROP.(MinRec, Vol 30)

See Also:

Links to other databases for Andyrobertsite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 -Google Images 4 -Google Scholar 5 -Handbook of Mineralogy (UofA) 6 -MinDAT 7 -MinMax(Deutsch) 8 -MinMax(English) 9 -Mineralienatlas (Deutsch) 10 -QUT Mineral Atlas

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Print or Cut-and-Paste your Andyrobertsite Specimen Label here :

Andyrobertsite

KCdCu5(AsO4)4[As(OH)2O2]·2(H2O)
Dana No: 42.9.2.3 Strunz No: VII/D.25-35
Locality:

Notes: