Brewsterite-Ba Mineral Data

General Brewsterite-Ba Information

Chemical Formula:

(Ba,Sr)Al2Si6O16•5(H2O)

Composition:

Molecular Weight = 693.44 gm

Barium 14.85 % Ba 16.58 % BaO

Strontium 3.16 % Sr 3.74 % SrO

Aluminum 7.78 % Al 14.70 % Al₂O₃

Silicon 24.30 % Si 51.99 % SiO₂

Hydrogen 1.45 % H 12.99 % H₂O

Oxygen 48.45 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ba_0.75Sr_0.25Al₂Si₆O₁₆•5(H₂O)

Environment:

Secondary mineral in metamorphosed calc-silicates. The Ba-dominant member of the brewsterite series.

IMA Status:

Approved IMA 1998 (Dana # Added)

Locality:

Discovered at the No. 4 wollastonite mine of the Gouverneur Talc Co., near Harrisville, Lewis County, New York, U.S.A. Link to MinDat.org Location Data.

Name Origin:

Named as the barium analogue of brewterite-Sr (formerly bariumbrewsterite).

Name Pronunciation:

Brewsterite-Ba + Pronunciation

Synonym:

Bariumbrewsterite

Brewsterite-Ba Image

Images:

Brewsterite-Ba

Comments: Colorless to off-white striated prismatic brewsterite-Ba crystals.
Location: Strontian, North West Highlands (Argyllshire), Scotland, UK. Scale: See Image.
© Rruff Database

Brewsterite-Ba Crystallography

Axial Ratios:

a:b:c =0.3852:1:0.4393

Cell Dimensions:

a = 6.78, b = 17.599, c = 7.733, Z = 2; beta = 94.47° V = 919.90 Den(Calc)= 2.50

Crystal System:

Monoclinic Space Group: P 2₁/m,P 2₁

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

By Intensity(I/I_o): 4.66(1), 2.922(0.8), 3.268(0.4),

Physical Properties of Brewsterite-Ba

Color:

White, Colorless, Pale pink.

Density:

2.453

Diaphaneity:

Transparent

Hardness:

5 - Apatite

Luster:

Vitreous (Glassy)

Optical Properties of Brewsterite-Ba

Gladstone-Dale:

CI meas= -0.007 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.012 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2069,KPDmeas= 0.2108,KC= 0.2094
Ncalc = 1.51 - 1.52

Optical Data:

Biaxial (+), a=1.51-1.514, b=1.512-1.516, g=1.523-1.528, bire=0.0130-0.0140, 2V(Calc)=46-48, 2V(Meas)=44-45.

Calculated Properties of Brewsterite-Ba

Electron Density:

Bulk Density (Electron Density)=2.40 gm/cc
note: Specific Gravity of Brewsterite-Ba =2.45 gm/cc.

Fermion Index:

Fermion Index = 0.04
Boson Index = 0.96

Photoelectric:

PE_{Brewsterite-Ba}= 65.44 barns/electron
U=PE_{Brewsterite-Ba} x rElectron Density= 157.17 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Brewsterite-Ba is Not Radioactive

Brewsterite-Ba Classification

Dana Class:

77.01.07.01a (77)Tectosilicate Zeolite group

(77.01)true zeolites

(77.01.07)Brewsterite and related species

77.01.07.01 Brewsterite-Sr (Sr,Ba)Al4Si12O32•10(H2O) P 2₁/m 2/m

77.01.07.01a Brewsterite-Ba! (Ba,Sr)Al2Si6O16•5(H2O) P 2₁/m,P 2₁ Mono

77.01.07.02 Yugawaralite CaAl2Si6O16•4(H2O) Pc m

77.01.07.03 Goosecreekite CaAl2Si6O16•5(H2O) P 2₁ 2

77.01.07.04 Roggianite Ca2[Be(OH)2Al2Si4O13]•<2•5(H2O) I 4/mcm 4/m 2/m 2/m

Strunz Class:

09.GE.20 09 - SILICATES (Germanates)

09.G - Tektosilicates with Zeolitic H2O

09.GE -Chains of T10O20 Tetrahedra

09.GE.20 Brewsterite-Ba! (Ba,Sr)Al2Si6O16•5(H2O) P 2₁/m,P 2₁ Mono

09.GE.20 Brewsterite-Sr (Sr,Ba)Al4Si12O32•10(H2O) P 2₁/m 2/m

Other Brewsterite-Ba Information

References:

NAME( CanMin, 8/99) PHYS. PROP.(Am.Min.,Vol.78,p1318,1993) OPTIC PROP.(Am.Min.,Vol.78,p1318,1993)

See Also:

Links to other databases for Brewsterite-Ba :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info

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Brewsterite-Ba

(Ba,Sr)Al2Si6O16•5(H2O)
Dana No: 77.01.07.01a Strunz No: 09.GE.20
Locality:

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