Molybdofornacite Mineral Data

General Molybdofornacite Information

Chemical Formula:

Pb2Cu[(As,P)O4][(Mo,Cr)O4](OH)

Composition:

Molecular Weight = 790.12 gm

Chromium 1.32 % Cr 2.53 % CrO₃

Copper 8.04 % Cu 9.05 % Cu₂O

Molybdenum 9.71 % Mo 14.57 % MoO₃

Arsenic 8.53 % As 13.09 % As₂O₅

Phosphorus 0.78 % P 1.80 % P₂O₅

Hydrogen 0.13 % H 1.14 % H₂O

Lead 52.45 % Pb 56.50 % PbO

Oxygen 19.03 % O

______ ______

100.00 % 98.68 % = TOTAL OXIDE

Empirical Formula:

Pb₂Cu(AsO₄)_0.9(PO₄)_0.2MoO₄_0.8CrO₄_0.2(OH)

Environment:

Deep oxidation zone of a dolostone-hosted hydrothermal polymetallic ore deposit.

IMA Status:

Approved IMA 1983

Locality:

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

Name Origin:

Named for its predominance of molybdenum and relation to fornacite.

Name Pronunciation:

Molybdofornacite + Pronunciation

Molybdofornacite Image

Images:

Molybdofornacite

Comments: Lime green, tabular crystals of molybdofornacite on matrix.
Location: Mahoney district, Tres Hermanas Mountains, Luna County, New Mexico, USA. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Molybdofornacite Crystallography

Axial Ratios:

a:b:c =1.3622:1:2.9683

Cell Dimensions:

a = 8.1, b = 5.946, c = 17.65, Z = 4; beta = 108.17° V = 807.68 Den(Calc)= 6.50

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 2₁/c

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

By Intensity(I/I_o): 3.32(1), 2.845(0.6), 2.979(0.6),

Physical Properties of Molybdofornacite

Cleavage:

None

Color:

Light green.

Density:

6.6

Diaphaneity:

Transparent

Fracture:

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

Habit:

Lath - Shaped like a small, thin plaster lath, tabular (rectangular) in shape.

Habit:

Pistolitic - > 3mm rounded spherical grains.

Hardness:

2-3 - Gypsum-Calcite

Luster:

Adamantine

Streak:

yellow

Optical Properties of Molybdofornacite

Gladstone-Dale:

CI meas= 0.006 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.009 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1692,KPDmeas= 0.1667,KC= 0.1677
Ncalc = 2.09 - 2.11

Optical Data:

Biaxial (+), a=2.05, g=2.15, bire=0.1000

Pleochroism (x):

pale yellow.

Pleochroism (y):

pale yellow.

Pleochroism (z):

yellowish green.

Calculated Properties of Molybdofornacite

Electron Density:

Bulk Density (Electron Density)=5.69 gm/cc
note: Specific Gravity of Molybdofornacite =6.60 gm/cc.

Fermion Index:

Fermion Index = 0.14
Boson Index = 0.86

Photoelectric:

PE_{Molybdofornacite}= 962.65 barns/electron
U=PE_{Molybdofornacite} x rElectron Density=5,472.81 barns/cc.

Radioactivity:

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

Molybdofornacite Classification

Dana Class:

43.04.03.03 (43)Compound Phosphates, etc.

(43.04)(Anhydrous Compound Anions With Hydroxyl or Halogen)

(43.04.03)Vauquelinite Group

43.04.03.01 Vauquelinite Pb2Cu(CrO4)(PO4)(OH) P 2₁/n 2/m

43.04.03.02 Fornacite Pb2Cu(CrO4)(AsO4)(OH) P 2₁/c 2/m

43.04.03.03 Molybdofornacite Pb2Cu[(As,P)O4][(Mo,Cr)O4](OH) P 2₁/c 2/m

Strunz Class:

07.FC.10 07 - SULFATES (SELENATES, TELLURATES)

07.F - Chromates

07.FC -With PO4, AsO4, SiO4

07.FC.10 Fornacite Pb2Cu(CrO4)(AsO4)(OH) P 2₁/c 2/m

07.FC.10 Molybdofornacite Pb2Cu[(As,P)O4][(Mo,Cr)O4](OH) P 2₁/c 2/m

Other Molybdofornacite Information

References:

NAME( AntBidBlaNic4) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic4)

See Also:

Links to other databases for Molybdofornacite :
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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Molybdofornacite

Pb2Cu[(As,P)O4][(Mo,Cr)O4](OH)
Dana No: 43.04.03.03 Strunz No: 07.FC.10
Locality:

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