Barrerite Mineral Data

General Barrerite Information

Chemical Formula:

(Na,K,Ca)2Al2Si7O18•6(H2O)

Composition:

Molecular Weight = 2,680.57 gm

Potassium 1.55 % K 1.86 % K₂O

Sodium 4.67 % Na 6.30 % Na₂O

Calcium 1.26 % Ca 1.76 % CaO

Magnesium 0.15 % Mg 0.26 % MgO

Aluminum 8.24 % Al 15.58 % Al₂O₃

Iron 0.02 % Fe 0.03 % FeO

Silicon 23.80 % Si 50.93 % SiO₂

Hydrogen 1.94 % H 17.33 % H₂O

Oxygen 58.36 % O

______ ______

100.00 % 94.03 % = TOTAL OXIDE

Empirical Formula:

Na_5.45K_1.06Ca_0.84Mg_0.17Al_8.19Fe²⁺_0.01Si_22.72O₇₂ï¿½25.78(H₂O)

Environment:

On the walls of large fractures in deeply weathered andesitic and rhyolitic lavas.

IMA Status:

Approved IMA 1974

Locality:

Found near Capo Pula, below South Efisio Tower, Nora, Sardinia, Italy. Link to MinDat.org Location Data.

Name Origin:

For Richard Maling Barrer (1910- ), New Zealand-born British teacher ad student of the chemistry of zeolites.

Name Pronunciation:

Barrerite + Pronunciation

Synonym:

ICSD 4396

PDF 29-1185

Barrerite Image

Images:

Barrerite

Comments: Barrerite, an extremely rare zeolite was found in large cavities on a tidal flat.
Location: Rocky Pass, Kuiu Island, Alaska. Scale: 5.5 x 6 cm.
© Fabre Minerals

Barrerite Crystallography

Axial Ratios:

a:b:c =0.7496:1:0.9803

Cell Dimensions:

a = 13.643, b = 18.2, c = 17.842, Z = 2; V = 4,430.21 Den(Calc)= 2.01

Crystal System:

Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Amma or Ammm

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

By Intensity(I/I_o): 4.054(1), 9.1(1), 3.028(0.8),

Physical Properties of Barrerite

Cleavage:

{???} Perfect

Color:

White, Pink.

Density:

2.13

Diaphaneity:

Transparent to Translucent

Hardness:

3-4 - Calcite-Fluorite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Barrerite

Gladstone-Dale:

CI meas= -0.048 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= -0.111 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.241,KPDmeas= 0.2274,KC= 0.217
Ncalc = 1.44 - 1.46

Optical Data:

Biaxial (-), a=1.4791, b=1.4851, g=1.4891, bire=0.0100, 2V(Calc)=78, 2V(Meas)=78.

Calculated Properties of Barrerite

Electron Density:

Bulk Density (Electron Density)=2.16 gm/cc
note: Specific Gravity of Barrerite =2.13 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Barrerite= 1.61 barns/electron
U=PE_Barrerite x r_electron= 3.47 barns/cc.

Radioactivity:

GRapi = 22.57 (Gamma Ray American Petroleum Institute Units)
Concentration of Barrerite per GRapi unit = 4.43 (%)

Estimated Radioactivity from Barrerite - barely detectable

Barrerite Classification

Dana Class:

77.01.04.05 (77)Tectosilicate Zeolite group

(77.01)true zeolites

(77.01.04)Heulandite and related species

77.01.04.01 Heulandite-Ca (Ca,Na)2-3Al3(Al,Si)2Si13O36•12(H2O) C 2/m, Cm, C 2 Mono

77.01.04.01a Heulandite-Na! (Na,Ca)2-3Al3(Al,Si)2Si13O36•12(H2O) C 2/m, Cm, C 2 Mono

77.01.04.01b Heulandite-K! (K,Na,Ca)2-3Al3(Al,Si)2Si13O36•12(H2O) C 2/m, Cm, C 2 2/m

77.01.04.01c Heulandite-Sr! (Sr,Na,Ca)2-3Al3(Al,Si)2Si13O36•12(H2O) C 2/m, Cm, C 2 Mono

77.01.04.01d Heulandite-Ba! (Ba,Ca,K,Na,Sr)5Al9Si27O72•22(H2O) C 2/m 2/m

77.01.04.02 Clinoptilolite-K (Na,K,Ca)2-3Al3(Al,Si)2Si13O36•12(H2O) C 2/m, C 2, Cm Mono

77.01.04.02a Clinoptilolite-Na! (Na,K,Ca)2-3Al3(Al,Si)2Si13O36•12(H2O) C 2/m, C 2, Cm Mono

77.01.04.02b Clinoptilolite-Ca! (Ca,Na,K)2-3Al3(Al,Si)2Si13O36•12(H2O) C 2/m 2/m

77.01.04.03 Stilbite-Ca NaCa4[Al8Si28O72]•n(H2O)(n=28-32) C 2/m 2/m

77.01.04.03a Stilbite-Na! Na3Ca3[Al8Si28O72]•n(H2O)(n=28-32) C 2/m 2/m

77.01.04.04 Stellerite CaAl2Si7O18•7(H2O) F mmm 2/m 2/m 2/m

77.01.04.05 Barrerite (Na,K,Ca)2Al2Si7O18•6(H2O) Amma or Ammm 2/m 2/m 2/m

Strunz Class:

09.GE.15 09 - SILICATES (Germanates)

09.G - Tektosilicates with Zeolitic H2O

09.GE -Chains of T10O20 Tetrahedra

09.GE.15 Barrerite (Na,K,Ca)2Al2Si7O18•6(H2O) Amma or Ammm 2/m 2/m 2/m

09.GE.15 Stellerite CaAl2Si7O18•7(H2O) F mmm 2/m 2/m 2/m

Other Barrerite Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Barrerite :
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

Search for Barrerite using:

[AOL] [Bing] [Dog Pile] [GeoScienceWorld] [HotBot] [Ixquick] [Lycos] [MAMMA] [Scirus] [Teoma] [WebCrawler] [Wikipedia] [YAHOO]

Visit our Advertisers for Barrerite :

Ask about Barrerite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

Print or Cut-and-Paste your Barrerite Specimen Label here :

Barrerite

(Na,K,Ca)2Al2Si7O18•6(H2O)
Dana No: 77.01.04.05 Strunz No: 09.GE.15
Locality:

Notes:

Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.