Rankachite Mineral Data

General Rankachite Information

Chemical Formula:

CaFe++V+++++4W++++++8O36•12(H2O)

Composition:

Molecular Weight = 2,562.65 gm

Calcium 1.56 % Ca 2.19 % CaO

Vanadium 7.95 % V 14.19 % V₂O₅

Iron 2.18 % Fe 2.80 % FeO

Hydrogen 0.94 % H 8.44 % H₂O

Tungsten 57.39 % W 72.38 % WO₃

Oxygen 29.97 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

CaFe²⁺V⁵⁺₄W₈O₃₆•12(H₂O)

Environment:

Secondary mineral in a mine.

IMA Status:

Approved IMA 1984

Locality:

Clara Mine, Wofach, Rankach Valley, Schwarzwald, Balden-Wurttenberg, Germany. Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Name Pronunciation:

Rankachite + Pronunciation

Rankachite Crystallography

Axial Ratios:

a:b:c =0.1944:1:0.1297

Cell Dimensions:

a = 8.17, b = 42.02, c = 5.45, Z = 2; V = 1,871.00 Den(Calc)= 4.55

Crystal System:

Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Pmmn

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

By Intensity(I/I_o): 10.64(1), 5.44(0.7), 4.57(0.6),

Physical Properties of Rankachite

Cleavage:

{100} Perfect, {010} Perfect

Color:

Brownish yellow, Dark brown.

Density:

4.5

Diaphaneity:

Translucent

Fracture:

Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.

Habit:

Acicular - Occurs as needle-like crystals.

Habit:

Encrustations - Forms crust-like aggregates on matrix.

Habit:

Rosette - Bundled tabular aggregates resembling rose flower petals.

Hardness:

2.5 - Finger Nail

Luster:

Adamantine - Greasy

Streak:

light brown

Optical Properties of Rankachite

Gladstone-Dale:

CI meas= 0.063 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= 0.073 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1952,KPDmeas= 0.1974,KC= 0.2106
Ncalc = 1.95 - 1.96

Optical Data:

Biaxial (-), a=1.77, b=1.925, g=1.97, bire=0.2000, 2V(Calc)=52, 2V(Meas)=58. Dispersion r << v.

Pleochroism (x):

yellow brown.

Pleochroism (y):

deep reddish brown.

Pleochroism (z):

deep reddish brown.

Calculated Properties of Rankachite

Electron Density:

Bulk Density (Electron Density)=4.00 gm/cc
note: Specific Gravity of Rankachite =4.50 gm/cc.

Fermion Index:

Fermion Index = 0.08
Boson Index = 0.92

Photoelectric:

PE_Rankachite= 699.88 barns/electron
U=PE_Rankachite x rElectron Density=2,797.17 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Rankachite is Not Radioactive

Rankachite Classification

Dana Class:

49.03.06.01 (49)Basic and Hydrated Molybdates and Tungstates

(49.03)(Hydrated, containing Hydroxyl or Halogen)

(49.03.06)Dana Group

49.03.06.01 Rankachite CaFeV4W8O36•12(H2O) Pmmn 2/m 2/m 2/m

Strunz Class:

07.GB.25 07 - SULFATES (SELENATES, TELLURATES)

07.G - Molybdates, Wolframates and Niobates

07.GB -With additional anions and/or H2O

07.GB.25 Rankachite CaFeV4W8O36•12(H2O) Pmmn 2/m 2/m 2/m

Other Rankachite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Dana8)

See Also:

Links to other databases for Rankachite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info

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

Rankachite

CaFe++V+++++4W++++++8O36•12(H2O)
Dana No: 49.03.06.01 Strunz No: 07.GB.25
Locality:

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