Perraultite Mineral Data

Perraultite Mineral Data +

General Perraultite Information

Chemical Formula:

(Na,Ca)2(Ba,K)2(Mn++,Fe++)8(Ti,Nb)4Si8O32(OH,F,O)6

Composition:

Molecular Weight = 1,766.01 gm

Potassium 1.11 % K 1.33 % K₂O

Barium 11.66 % Ba 13.02 % BaO

Sodium 1.95 % Na 2.63 % Na₂O

Calcium 1.13 % Ca 1.59 % CaO

Titanium 10.30 % Ti 17.19 % TiO₂

Manganese 15.55 % Mn 20.08 % MnO

Niobium 1.05 % Nb 1.51 % Nb₂O₅

Iron 9.49 % Fe 12.20 % FeO

Silicon 12.72 % Si 27.22 % SiO₂

Hydrogen 0.26 % H 2.30 % H₂O

Oxygen 32.61 % O

Fluorine 2.15 % F 2.15 % F

- % F -0.91 % -O=F₂

______ ______

100.00 % 100.32 % = TOTAL OXIDE

Empirical Formula:

Na_1.5K_0.5Ca_0.5Ba_1.5Mn²⁺₅Fe²⁺₃Ti_3.8Nb_0.2Si₈O₃₂(OH)_3.5F₂(H₂O)_0.5

Environment:

In pegmatite dikes. Probable analog of jinshajiangite.

IMA Status:

Approved IMA 1991

Locality:

DeMix quarry, Mont Saint Hilaire, Quebec, Canada. Link to MinDat.org Location Data.

Name Origin:

Named for Guy Perault (1937-) of Ecole Polytechnique, Montreal, Canada.

Synonym:

ICSD 87533

IMA1984-033

PDF 45-1346

Perraultite Image

Images:

Perraultite

Comments: Dark red prismatic crystal of perraultite to 1mm in matrix.
Location: Mariupol massif, Azov Sea Region, Ukraine. Scale: Picture size 3 mm.
© Tom Loomis / Dakota Matrix

Perraultite Crystallography

Axial Ratios:

a:b:c =0.7492:1:1.7536

Cell Dimensions:

a = 10.371, b = 13.841, c = 24.272, Z = 4; beta = 121.19° V = 2,980.51 Den(Calc)= 3.94

Crystal System:

Monoclinic - SphenoidalH-M Symbol (2) Space Group: C 2

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

By Intensity(I/I_o): 3.474(1), 10.43(0.42), 2.606(0.4),

Physical Properties of Perraultite

Cleavage:

[001] Perfect

Color:

Orange brown.

Density:

3.71

Diaphaniety:

Transparent to Translucent

Fracture:

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

Habit:

Twinning Common - Crystals are usually twinned.

Hardness:

4 - Fluorite

Luster:

Vitreous (Glassy)

Streak:

light brown

Optical Properties of Perraultite

Gladstone-Dale:

CI meas= 0.045 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.1 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2043,KPDmeas= 0.217,KC= 0.2271

Optical Data:

Biaxial (-), a=1.785, b=1.81, g=1.82, bire=0.0350, 2V(Calc)=62, 2V(Meas)=66. Dispersion r << v strong.

Pleochroism (x):

light yellow.

Pleochroism (y):

light yellow.

Pleochroism (z):

dark orange brown.

Calculated Properties of Perraultite

Electron Density:

r_electron=3.52 gm/cc
note: r_Perraultite=3.71 gm/cc.

Fermion Index

Fermion Index = 0.04223
Boson Index = 0.95777

Photoelectric:

PE_Perraultite= 60.38 barns/electron
U=PE_Perraultite x r_electron= 212.40 barns/cc.

Radioactivity:

GRapi = 15.13 (Gamma Ray American Petroleum Institute Units)

Estimated Radioactivity from Perraultite - barely detectable

Perraultite Classification

Dana Class:

78.1.5.2 (78)Unclassified silicates

(78.1)possible nesosilicates

(78.1.5)Jinshianghite group

78.1.5.1 Jinshajiangite Na2K5BaCa(Fe,Mn)8(Ti,Fe,Nb,Zr)4Si8O32(O,F,H2O)6 C 2/m,Cm,C 2 Mono

78.1.5.2 Perraultite (Na,Ca)2(Ba,K)2(Mn,Fe)8(Ti,Nb)4Si8O32(OH,F,O)6 C 2 2

Strunz Class:

VIII/D.03-20 VIII - Silicates

VIII/D - Unclassified silicates, mostly cations of small size Mg, Fe, Mn, Cu

VIII/D.03 - Jinshajiangite - Perraultite series

VIII/D.03-10 Jinshajiangite Na2K5BaCa(Fe,Mn)8(Ti,Fe,Nb,Zr)4Si8O32(O,F,H2O)6 C 2/m,Cm,C 2 Mono

VIII/D.03-20 Perraultite (Na,Ca)2(Ba,K)2(Mn,Fe)8(Ti,Nb)4Si8O32(OH,F,O)6 C 2 2

Other Perraultite Information

References:

NAME( Dana8) PHYS. PROP.(Am.Min.,Vol.86) OPTIC PROP.(Dana8)

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Perraultite

(Na,Ca)2(Ba,K)2(Mn++,Fe++)8(Ti,Nb)4Si8O32(OH,F,O)6
Dana No: 78.1.5.2 Strunz No: VIII/D.03-20
Locality:

Notes: