Rollandite Mineral Data

Rollandite Mineral Data

General Rollandite Information

Chemical Formula:

Cu3(AsO4)2·4(H2O)

Composition:

Molecular Weight = 543.29 gm

Copper 36.26 % Cu 45.39 % CuO

Arsenic 27.58 % As 42.31 % As₂O₅

Hydrogen 1.41 % H 12.60 % H₂O

Oxygen 34.75 % O

______ ______

100.00 % 100.29 % = TOTAL OXIDE

Empirical Formula:

Cu_3.1(AsO₄)₂·3.8(H₂O)

Environment:

Secondary mineral in old Cu mines. New structure-type.

IMA Status:

Approved IMA 1998 (Dana # Added)

Locality:

Cu mines of Roua at the western margin of the Barrot Dome, Alpes-Maritimes, France. Link to MinDat.org Location Data.

Name Origin:

Named for Pierre Rolland (1940-), an eminent mineral collector of the Roua mines.

Synonym:

ICSD 90026

IMA1998-001

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Rollandite Crystallography

Axial Ratios:

a:b:c =0.3335:1:0.5704

Cell Dimensions:

a = 5.6906, b = 17.061, c = 9.732, Z = 4; V = 944.85 Den(Calc)= 3.82

Crystal System:

Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: P nma

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

By Intensity(I/I_o): 8.52(1)(020), 3.221(0.9)(141,051), 3.721(0.6)(131),3.102(0.4)(132), 2.795(0.35)(142), 2.817(0.35)(103,033), 2.133(0.25)(080,251), 2.35(0.25)(143,053), 2.366(0.2)(240,071),

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Sarp H , Cerny R , European Journal of Mineralogy , 12 (2000) p.1045-1050, Rollandite, Cu3(AsO4)2.4H2O, a new mineral: its description and crystal structure

Physical Properties of Rollandite

Cleavage:

[001] Good

Color:

Bottle green.

Density:

3.9

Diaphaniety:

Transparent

Fracture:

Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).

Habit:

Aggregates - Made of numerous individual crystals or clusters.

Hardness:

4-4.5 - Between Fluorite and Apatite

Luster:

Vitreous (Glassy)

Streak:

light green

Optical Properties of Rollandite

Gladstone-Dale:

CI meas= -0.025 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.046 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1972,KPDmeas= 0.1932,KC= 0.1885

Optical Data:

Biaxial (-), a=1.745, b=1.755, g=1.76, bire=0.0150, 2V(Calc)=70, 2V(Meas)=71. Dispersion strong, r < v.

Calculated Properties of Rollandite

Electron Density:

r_electron=3.70 gm/cc
note: r_Rollandite=3.90 gm/cc.

Fermion Index

Fermion Index = 0.00016
Boson Index = 0.99984

Photoelectric:

PE_Rollandite= 34.93 barns/electron
U=PE_Rollandite x r_electron= 129.32 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Rollandite is Not Radioactive

Rollandite Classification

Dana Class:

40.3.4.2 (40)Hydrated Phosphates, etc

(40.3)where (A++)3 (XO4)2 · x(H2O)

(40.3.4)Dana Group

40.3.4.1 Hopeite Zn3(PO4)2·4(H2O) P nma 2/m 2/m 2/m

40.3.4.2 Rollandite ! Cu3(AsO4)2·4(H2O) P nma 2/m 2/m 2/m

Strunz Class:

VII/C.06-37 VII - Phosphates, Arsenates and Vanadates

VII/C - Water-bearing phosphates without unfamiliar anions. cations of medium and small size: Be and Mn, Fe, Cu, Zn, Mg

VII/C.06 - Cobaltkoritnigite - Geigerite series

VII/C.06-10 Cobaltkoritnigite (Co,Zn)(AsO3OH)·(H2O) P1 1

VII/C.06-20 Koritnigite ZnHAsO4·(H2O) P1 1

VII/C.06-30 Geminite Cu2As2O7·3(H2O) P1 or P1 Tri

VII/C.06-32 Pushcharovskite! Cu(AsO3OH)·1.5(H2O) P1 or P1 Tri

VII/C.06-35 Yvonite! Cu(AsO3OH)·2(H2O) P1 1

VII/C.06-37 Rollandite Cu3(AsO4)2·4(H2O) P nma 2/m 2/m 2/m

VII/C.06-40 Chudobaite (Mg,Zn)5(AsO3OH)2(AsO4)2·10(H2O) P1 1

VII/C.06-50 Lindackerite CuCu4(AsO4)2(AsO3OH)2·~9(H2O) P1 1

VII/C.06-60 Geigerite Mn5(AsO3OH)2(AsO4)2·10(H2O) P1 1

Other Rollandite Information

References:

NAME( AmMin, vol 86, p 768) PHYS. PROP.(AmMin, vol 86, p 768) OPTIC PROP.(AmMin, vol 86, p 768)

See Also:

Links to other databases for Rollandite :
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 11 - WWW-MINCRYST

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

Rollandite

Cu3(AsO4)2·4(H2O)
Dana No: 40.3.4.2 Strunz No: VII/C.06-37
Locality:

Notes: