Epistilbite Mineral Data

General Epistilbite Information

Chemical Formula:

CaAl2Si6O16•5(H2O)

Composition:

Molecular Weight = 608.62 gm

Calcium 6.59 % Ca 9.21 % CaO

Aluminum 8.87 % Al 16.75 % Al₂O₃

Silicon 27.69 % Si 59.23 % SiO₂

Hydrogen 1.66 % H 14.80 % H₂O

Oxygen 55.20 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

CaAl₂Si₆O₁₆•5(H₂O)

Environment:

Alteration product in basalts.

IMA Status:

Valid Species (Pre-IMA) 1826

Locality:

Berufjord, Iceland. Link to MinDat.org Location Data.

Name Origin:

From the Greek epi - "near" and the mineral Stilbite.

Name Pronunciation:

Epistilbite + Pronunciation

Synonym:

ICSD 82770

PDF 39-1381

Epistilbite Image

Images:

Epistilbite Quartz

Comments: White epistilbite cluster 25 mm across on amethyst quartz crystal matrix.
Location: Sawda, Jalgaon, Maharashtra, India. Scale: 10x8x5 cm.
© John Betts - Fine Minerals

Epistilbite Crystallography

Axial Ratios:

a:b:c =0.512:1:0.5755

Cell Dimensions:

a = 9.083, b = 17.738, c = 10.209, Z = 4; alpha = 89.95°, beta = 124.58°, gamma = 90° V = 1,354.23 Den(Calc)= 2.98

Crystal System:

Triclinic - Pedial H-M Symbol (1) Space Group: C1

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

By Intensity(I/I_o): 3.45(1), 3.21(0.9), 8.89(0.9),

Physical Properties of Epistilbite

Cleavage:

{010} Perfect

Color:

White, Yellowish white, Reddish white, Brownish white.

Density:

2.2 - 2.3, Average = 2.25

Diaphaneity:

Transparent to translucent

Fracture:

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

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Habit:

Spherical - Spherical, rounded aggregates.

Habit:

Twinning Common - Crystals are usually twinned.

Hardness:

4-5 - Fluorite-Apatite

Luminescence:

Non-fluorescent.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Epistilbite

Gladstone-Dale:

CI meas= 0.008 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.251 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1705,KPDmeas= 0.2258,KC= 0.2276
Ncalc = 1.5 - 1.68

Optical Data:

Biaxial (-), a=1.502, b=1.51, g=1.512, bire=0.0100, 2V(Calc)=52, 2V(Meas)=44. Dispersion relatively strong.

Pleochroism (x):

colorless.

Pleochroism (y):

colorless.

Pleochroism (z):

colorless.

Calculated Properties of Epistilbite

Electron Density:

Bulk Density (Electron Density)=2.28 gm/cc
note: Specific Gravity of Epistilbite =2.25 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Epistilbite= 2.15 barns/electron
U=PE_Epistilbite x rElectron Density= 4.91 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Epistilbite is Not Radioactive

Epistilbite Classification

Dana Class:

77.01.06.02 (77)Tectosilicate Zeolite group

(77.01)true zeolites

(77.01.06)Mordenite and related species

77.01.06.01 Mordenite (Ca,Na2,K2)Al2Si10O24•7(H2O) C mc2₁ mm2

77.01.06.02 Epistilbite CaAl2Si6O16•5(H2O) C1 1

77.01.06.03 Maricopaite Pb7Ca2(Si,Al)48O100•32(H2O) Cm2m 2/m 2/m 2/m

77.01.06.04 Dachiardite-Ca (Ca,Na2,K2)5Al10Si38O96•25(H2O) C 2/m 2/m

77.01.06.05 Dachiardite-Na (Na2,Ca,K2)4Al4Si20O48•13(H2O) C 2/m 2/m

77.01.06.06 Ferrierite-Mg (Mg,Na,K)2Mg(Si,Al)18O36•9(H2O) Pnnm 2/m 2/m 2/m

77.01.06.06a Ferrierite-K! (K,Na)2Mg(Si,Al)18O36•9(H2O) Pnnm 2/m 2/m 2/m

77.01.06.06b Ferrierite-Na! (Na,K)2Mg(Si,Al)18O36•9(H2O) P 2₁/n 2/m

77.01.06.07 Boggsite NaCa2(Al5Si19O48)•17(H2O) I mma 2/m 2/m 2/m

77.01.06.08 Gottardiite! Na3Mg3Ca5Al19Si117O272•93(H2O) C mca 2/m 2/m 2/m

77.01.06.09 Terranovaite! (Na,Ca)8(Si68Al12)O160•29(H2O) C mcm 2/m 2/m 2/m

77.01.06.10 Mutinaite! Na3Ca4Si85Al11O192•60(H2O) P nma 2/m 2/m 2/m

77.01.06.12 Direnzoite! NaK6MgCa2(Al13Si47O120)•36H2O Pmmn 2/m 2/m 2/m

Strunz Class:

09.GD.45 09 - SILICATES (Germanates)

09.G - Tektosilicates with Zeolitic H2O

09.GD -Chains of 6-membered rings � tabular zeolites

09.GD.45 Epistilbite CaAl2Si6O16•5(H2O) C1 1

Other Epistilbite Information

References:

NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32)

See Also:

Links to other databases for Epistilbite :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - EUROmin Project
5 - Ecole des Mines de Paris
6 - GeoScienceWorld
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - MinDAT
12 - Mineralienatlas (Deutsch)
13 - Online Mineral Museum
14 - QUT Mineral Atlas
15 - Ruff.Info
16 - WWW-MINCRYST
17 - Zeolite Database by Bruno Herreros

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Epistilbite

CaAl2Si6O16•5(H2O)
Dana No: 77.01.06.02 Strunz No: 09.GD.45
Locality:

Notes:

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