Montesommaite Mineral Data

General Montesommaite Information

Chemical Formula:

(K,Na)9Al9Si23O64•10(H2O)

Composition:

Molecular Weight = 2,433.32 gm

Potassium 13.82 % K 16.65 % K₂O

Sodium 0.19 % Na 0.25 % Na₂O

Aluminum 10.42 % Al 19.69 % Al₂O₃

Silicon 26.09 % Si 55.80 % SiO₂

Hydrogen 0.83 % H 7.40 % H₂O

Oxygen 48.66 % O

______ ______

100.00 % 99.80 % = TOTAL OXIDE

Empirical Formula:

K_8.6Na_0.2Al_9.4Si_22.6O₆₄•10(H₂O)

Environment:

In volcanic ejecta.

IMA Status:

Approved IMA 1990

Locality:

Monte Somma, Pollena, Camania, Italy. Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Name Pronunciation:

Montesommaite + Pronunciation

Synonym:

ICSD 40111(subcell)

IMA1988-038

PDF 46-1351

Montesommaite Image

Images:

Montesommaite

Comments: Translucent prismatic montesommaite crystals in vugs.
Location: Pollena Quarry, Vesuvius, Naples, Campania, Italy. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Montesommaite Crystallography

Axial Ratios:

a:b:c =1:1:1.7137

Cell Dimensions:

a = 10.099, b = 10.099, c = 17.307, Z = 1; V = 1,765.14 Den(Calc)= 2.29

Crystal System:

Orthorhombic - Pyramidal H-M Symbol (mm2) Space Group: F dd2

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

By Intensity(I/I_o): 3.13(1), 3.299(1), 6.589(0.75),

Physical Properties of Montesommaite

Cleavage:

None

Color:

Colorless.

Density:

2.34

Diaphaneity:

Transparent

Habit:

Pyramidal - Crystals are shaped like pyramids.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Montesommaite

Gladstone-Dale:

CI meas= -0.001 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.022 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2199,KPDmeas= 0.2152,KC= 0.2151
Ncalc = 1.49 - 1.5

Optical Data:

Biaxial (-), a=1.498, b=1.506, g=1.507, bire=0.0090, 2V(Calc)=38, 2V(Meas)=35.

Calculated Properties of Montesommaite

Electron Density:

Bulk Density (Electron Density)=2.34 gm/cc
note: Specific Gravity of Montesommaite =2.34 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_{Montesommaite}= 2.69 barns/electron
U=PE_{Montesommaite} x r_electron= 6.30 barns/cc.

Radioactivity:

GRapi = 199.31 (Gamma Ray American Petroleum Institute Units)
Concentration of Montesommaite per GRapi unit = 0.50 (%)

Estimated Radioactivity from Montesommaite - barely detectable

Montesommaite Classification

Dana Class:

77.01.03.12 (77)Tectosilicate Zeolite group

(77.01)true zeolites

(77.01.03)Gismondine and related species

77.01.03.01 Gismondine Ca2Al4Si4O16•9(H2O) P 2₁/c 2/m

77.01.03.02 Amicite K2Na2Al4Si4O16•5(H2O) I2 2

77.01.03.03 Garronite Na2Ca5Al12Si20O64•27(H2O) I 4₁/a 4/m

77.01.03.04 Gobbinsite (Na2,Ca)2K2Al6Si10O32•12(H2O) P mn2₁ mm2

77.01.03.05 Harmotome (Ba,Na,K)1-2(Si,Al)8O16•6(H2O) P 2₁/m 2/m

77.01.03.06 Phillipsite-Na (Na,K,Ca)1-2(Si,Al)8O16•6(H2O) P 2₁/m 2/m

77.01.03.06a Phillipsite-Ca! (Ca,K,Na)1-2(Si,Al)8O16•6(H2O) P 2₁/m 2/m

77.01.03.06b Phillipsite-K! (K,Na,Ca)1-2(Si,Al)8O16•6(H2O) P 2₁/m 2/m

77.01.03.08 Perlialite K8Tl4Al12Si24O72•20(H2O) P 6/mmm 6/m 2/m 2/m

77.01.03.09 Paulingite-K (K2,Ca,Na2,Ba)5Al10Si35O90•45(H2O) Im3m 4/m 3 2/m

77.01.03.09a Paulingite-Na! (Na2,K2,Ca,Ba)5Al10Si35O90•45(H2O) Im3m 4/m 3 2/m

77.01.03.09b Paulingite-Ca! (Ca,K,Na,Ba)5[Al10Si35O84]•34(H2O) Im3m 4/m 3 2/m

77.01.03.10 Mazzite-Mg K2CaMg2(Al,Si)36O72•28(H2O) P 6₃/mmc 6/m 2/m 2/m

77.01.03.10a Mazzite-Na! Na8Al8Si28O72•30H2O P 6₃/mmc 6/m 2/m 2/m

77.01.03.11 Merlinoite (K,Ca,Na,Ba)7Si23Al9O64•23(H2O) I mmm 2/m 2/m 2/m

77.01.03.12 Montesommaite (K,Na)9Al9Si23O64•10(H2O) F dd2 mm2

Strunz Class:

09.GB.30 09 - SILICATES (Germanates)

09.G - Tektosilicates with Zeolitic H2O

09.GB -Chains of single connected 4-membered rings

09.GB.30 Montesommaite (K,Na)9Al9Si23O64•10(H2O) F dd2 mm2

Other Montesommaite Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Am.Min.,Vol.75,p1415-1420,1990) OPTIC PROP.(Am.Min.,Vol.75,p1415-1420,1990)

See Also:

Links to other databases for Montesommaite :
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
15 - WWW-MINCRYST
16 - Zeolite Database by Bruno Herreros

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Montesommaite

(K,Na)9Al9Si23O64•10(H2O)
Dana No: 77.01.03.12 Strunz No: 09.GB.30
Locality:

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