Muscovite Mineral Data

Muscovite Mineral Data +

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General Muscovite Information

Chemical Formula:

KAl2(Si3Al)O10(OH,F)2

Composition:

Molecular Weight = 398.71 gm

Potassium 9.81 % K 11.81 % K₂O

Aluminum 20.30 % Al 38.36 % Al₂O₃

Silicon 21.13 % Si 45.21 % SiO₂

Hydrogen 0.46 % H 4.07 % H₂O

Oxygen 47.35 % O

Fluorine 0.95 % F 0.95 % F

- % F -0.40 % -O=F₂

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

KAl₃Si₃O₁₀(OH)_1.8F_0.2

Environment:

Granites and pegmatites.

IMA Status:

Valid Species (Pre-IMA) 1850

Locality:

Common world wide. Link to MinDat.org Location Data.

Name Origin:

From Muscovy glass, alluding to the Russian province of Muscovy.

Synonym:

Binnite (Ba)

Fuchsite (Cr)

Isinglass

Potash Mica

Muscovite Image

Images:

Muscovite Fluorapatite Beryl Apatite

Comments: Pink crystals of fluorapatite with pale blue beryl (aquamarine) on books of muscovite crystals.
Location: Nagar area, Gilgit district, Northern Areas, Pakistan. Scale: 3 x 3 cm.
© Dan Weinrich

Images:

Muscovite

Comments: Pseudo-hexagonal crystalline aggregate of muscovite.
Location: Conselheiro Pena, Minas Gerais, Brazil. Scale: Crystal size 2 cm.
© Dave Barthelmy

Images:

Muscovite

Comments: Seams of green muscovite var. fuchsite in quartz matrix with minor pyrite crystals.
Location: Wolfe's Neck locality, Freeport, Cumberland Co., Maine, USA. Scale: 7x5x4 cm.
© John Betts - Fine Minerals

Images:

Muscovite Aluminoceladonite

Comments: Large, 1cm, purple crystals of muscovite/leucophyllite, (var. alurgite which is an intermediate composition to muscovite and leucophyllite (aluminoceladonite).
Location: Ultevis, Sweden. Scale: 5x3.5x3cm.
© Tom Loomis / Dakota Matrix

Muscovite Crystallography

Axial Ratios:

a:b:c =0.5747:1:2.2203

Cell Dimensions:

a = 5.19, b = 9.03, c = 20.05, Z = 4; beta = 95.5° V = 935.33 Den(Calc)= 2.83

Crystal System:

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

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

By Intensity(I/I_o): 3.32(1), 9.95(0.95), 2.57(0.55),

Forms:

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Crystal Structure:

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Richardson S M , Richardson J W , American Mineralogist , 67 (1982) p.69-75, Crystal structure of a pink muscovite from Archer s Post, Kenya: Implications, for reverse pleochroism in dioctahedral micas

View Additional jPOWD Structure files for Muscovite
[1] [11] [12] [13] [14] [15] [16] [17] [2] [20] [21] [3] [4] [5] [6] [7] [8]

Physical Properties of Muscovite

Cleavage:

[001] Perfect

Color:

White, Gray, Silver white, Brownish white, Greenish white.

Density:

2.77 - 2.88, Average = 2.82

Diaphaniety:

Transparent to translucent

Fracture:

Brittle - Sectile - Brittle fracture with slightly sectile shavings possible.

Habit:

Foliated - Two dimensional platy forms.

Habit:

Massive - Lamellar - Distinctly foliated fine-grained forms.

Habit:

Micaceous - Platy texture with "flexible" plates.

Hardness:

2-2.5 - Gypsum-Finger Nail

Luminescence:

None.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Muscovite

Gladstone-Dale:

CI meas= 0.015 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.017 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2073,KPDmeas= 0.2077,KC= 0.2109

Optical Data:

Biaxial (?), a=1.552-1.574, b=1.582-1.61, g=1.586-1.616, bire=0.0340-0.0420, 2V(Calc)=38-42, 2V(Meas)=30-47. Dispersion weak to distinct, r > v.

Pleochroism (x):

colorless or robins egg blue.

Pleochroism (y):

colorless, very pale green, yellow, or pale yellowish green.

Pleochroism (z):

colorless, pale green, blue green, or bright chrome green.

Calculated Properties of Muscovite

Electron Density:

r_electron=2.81 gm/cc
note: r_Muscovite=2.83 gm/cc.

Fermion Index

Fermion Index = 0.0101
Boson Index = 0.9899

Photoelectric:

PE_Muscovite= 2.39 barns/electron
U=PE_Muscovite x r_electron= 6.72 barns/cc.

Radioactivity:

GRapi = 140.52 (Gamma Ray American Petroleum Institute Units)

Estimated Radioactivity from Muscovite - barely detectable

Muscovite Classification

Dana Class:

71.2.2a.1 (71)Phyllosilicate Sheets of Six-Membered Rings

(71.2)with 2:1 Layers

(71.2.2a)Mica Group (Muscovite subgroup)

71.2.2a.1 Muscovite KAl2(Si3Al)O10(OH,F)2 C 2/m 2/m

71.2.2a.2 Paragonite NaAl2(Si3Al)O10(OH)2 C 2/c,Cc Mono

71.2.2a.3 Chernykhite (Ba,Na)V,Al)2(Si,Al)4O10(OH)2 C 2/c 2/m

71.2.2a.4 Roscoelite K(V,Al,Mg)2AlSi3O10(OH)2 C 2/m 2/m

71.2.2a.5 Glauconite (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2 C 2/m 2/m

71.2.2a.6 Celadonite K(Mg,Fe)(Fe,Al)[Si4O10](OH)2 C 2/m 2/m

71.2.2a.6b Ferroceladonite! K2FeFeSi8O20(OH)4 C 2/m 2/m

71.2.2a.6c Ferro-aluminoceladonite! K2Fe2Al2Si8O20(OH)4 C 2/m 2/m

71.2.2a.6d Aluminoceladonite! KAl(Mg,Fe)[]Si4O10(OH)2 2/m

71.2.2a.6e Chromceladonite! KCrMg(Si4O10)(OH)2 C 2 2

71.2.2a.7 Tobelite (NH4,K)Al2(Si3Al)O10(OH)2 C 2/m 2/m

71.2.2a.8 Nanpingite Cs(Al,Mg,Fe,Li)2(Si3Al)O10(OH,F)2 C 2/c 2/m

71.2.2a.9 Boromuscovite KAl2(Si3B)O10(OH,F)2 C 2/m 2/m

71.2.2a.10 Montdorite (K,Na)(Fe,Mn,Mg)2.5[Si4O10](F,OH)2 C 2/c 2/m

71.2.2a.11 Chromphyllite! (K,Ba)(Cr,Al)2[AlSi3O10](OH,F)2 C 2c 2/m

71.2.2a.12 Shirokshinite! K(NaMg2)Si4O10F2 C 2/m 2/m

Strunz Class:

VIII/H.10-70 VIII - Silicates

VIII/H - Phyllosilicates (layered) Mica like layered silicates with [Si4O10]4- and related groups

VIII/H.10 - Mica group, Muscovite series

VIII/H.10-10 Aluminoceladonite! KAl(Mg,Fe)[]Si4O10(OH)2 2/m

VIII/H.10-20 Ferro-aluminoceladonite! K2Fe2Al2Si8O20(OH)4 C 2/m 2/m

VIII/H.10-30 Celadonite K(Mg,Fe)(Fe,Al)[Si4O10](OH)2 C 2/m 2/m

VIII/H.10-35 Chromceladonite! KCrMg(Si4O10)(OH)2 C 2 2

VIII/H.10-40 Ferroceladonite! K2FeFeSi8O20(OH)4 C 2/m 2/m

VIII/H.10-50 Paragonite NaAl2(Si3Al)O10(OH)2 C 2/c,Cc Mono

VIII/H.10-60 Boromuscovite KAl2(Si3B)O10(OH,F)2 C 2/m 2/m

VIII/H.10-70 Muscovite KAl2(Si3Al)O10(OH,F)2 C 2/m 2/m

VIII/H.10-80 Chromphyllite! (K,Ba)(Cr,Al)2[AlSi3O10](OH,F)2 C 2c 2/m

VIII/H.10-90 Roscoelite K(V,Al,Mg)2AlSi3O10(OH)2 C 2/m 2/m

VIII/H.10-95 Ganterite! [Ba0.5(Na,K)0.5]Al2(Si2.5Al1.5O10)(OH)2 C 2/c 2/m

VIII/H.10-100 Tobelite (NH4,K)Al2(Si3Al)O10(OH)2 C 2/m 2/m

VIII/H.10-110 Nanpingite Cs(Al,Mg,Fe,Li)2(Si3Al)O10(OH,F)2 C 2/c 2/m

Other Muscovite Information

References:

NAME( ODonoghue90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Heinrich65)

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Muscovite

KAl2(Si3Al)O10(OH,F)2
Dana No: 71.2.2a.1 Strunz No: VIII/H.10-70
Locality:

Notes: