Herschelite Mineral Data

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General Herschelite Information

Chemical Formula:

(Na,Ca,K)AlSi2O6•3(H2O)

Composition:

Molecular Weight = 261.30 gm

Potassium 2.99 % K 3.60 % K₂O

Sodium 7.04 % Na 9.49 % Na₂O

Calcium 0.77 % Ca 1.07 % CaO

Aluminum 11.36 % Al 21.46 % Al₂O₃

Silicon 20.42 % Si 43.69 % SiO₂

Hydrogen 2.31 % H 20.68 % H₂O

Oxygen 55.11 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Na_0.8K_0.2Ca_0.05Al_1.1Si_1.9O₆•3(H₂O)

Environment:

In cavities in basalts. Species name changed to chabazite-Na by the IMA Commission on zeolites.

IMA Status:

Discredited IMA 1997 - Valid Species (Pre-IMA) 1825

Locality:

From Aci Castello and nearby on the flanks of Mt. Etna, Sicily. Link to MinDat.org Location Data.

Name Origin:

Named in 1825 for John Frederick William Herschel (1792-1871), British astronomer.

Name Pronunciation:

Herschelite + Pronunciation

Synonym:

Discredited IMA 1997

Herschelite Image

Images:

Herschelite Chabazite-Na

Comments: Rounded transparent crystals of chabazite-Na (herschelite).
Location: Horseshoe Dam, Maricopa County, Arizona, USA. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Herschelite Crystallography

Axial Ratios:

a:c = 1:1.09442

Cell Dimensions:

a = 13.799, c = 15.102, Z = 12; V = 2,490.35 Den(Calc)= 2.09

Crystal System:

Trigonal - Hexagonal ScalenohedralH-M Symbol (3 2/m) Space Group: R 3m

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

By Intensity(I/I_o): 2.93(1), 4.32(0.65), 6.36(0.5),5.03(0.4), 2.987(0.3), 3.88(0.25), 6.89(0.2),

Physical Properties of Herschelite

Cleavage:

{1011} Distinct

Color:

Colorless, White.

Density:

2.08 - 2.16, Average = 2.12

Diaphaneity:

Transparent to Translucent

Fracture:

Brittle - Uneven - Very brittle fracture producing uneven fragments.

Habit:

Platy - Sheet forms (e.g. micas).

Hardness:

4-5 - Fluorite-Apatite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Herschelite

Gladstone-Dale:

CI meas= 0.036 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.022 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2279,KPDmeas= 0.2246,KC= 0.233
Ncalc = 1.48 - 1.5

Optical Data:

Uniaxial (-), e=1.471-1.479, w=1.474-1.481, bire=0.0020-0.0030.

Calculated Properties of Herschelite

Electron Density:

Bulk Density (Electron Density)=2.12 gm/cc
note: Specific Gravity of Herschelite =2.09 gm/cc.

Fermion Index:

Fermion Index = 0.0098189704
Boson Index = 0.9901810296

Photoelectric:

PE_Herschelite= 1.66 barns/electron
U=PE_Herschelite x r_electron= 3.52 barns/cc.

Radioactivity:

GRapi = 43.80 (Gamma Ray American Petroleum Institute Units)
Concentration of Herschelite per GRapi unit = 2.28 (%)

Estimated Radioactivity from Herschelite - barely detectable

Herschelite Classification

Dana Class:

77.01.02.02 (77)Tectosilicate Zeolite group

(77.01)true zeolites

(77.01.02)Chabazite and related species

77.01.02.01 Chabazite-Ca (Ca0.5,Na,K)4[Al4Si8O24]•12H2O P1 1

77.01.02.01a Chabazite-Na! (Na2,K2,Ca,Mg)[Al2Si4O12]•6(H2O) R 3m 3 2/m

77.01.02.01b Chabazite-K! (K2,Ca,Na2,Mg)[Al2Si4O12]•6(H2O) R 3m 3 2/m

77.01.02.01c Chabazite-Sr! (Sr,Ca,K2,Na2)[Al2Si4O12]•6(H2O) R 3m 3 2/m

77.01.02.02 Herschelite? (Na,Ca,K)AlSi2O6•3(H2O) R 3m 3 2/m

77.01.02.03 Willhendersonite KCaAl3Si3O12•5(H2O) P1 1

77.01.02.04 Offretite (K2,Ca,Mg)2.5Al5Si13O36•15(H2O) P 6m2 6 m2

77.01.02.05 Erionite-Na (Na2,K2,Ca)2[Al4Si14O36]•15(H2O) P 6₃/mmc 6/m 2/m 2/m

77.01.02.05a Erionite-K! (K2,Ca,Na2)2[Al4Si14O36]•15(H2O) P 6₃/mmc 6/m 2/m 2/m

77.01.02.05b Erionite-Ca! (Ca,K2,Na2)2[Al4Si14O36]•15(H2O) P 6₃/mmc 6/m 2/m 2/m

77.01.02.06 Gmelinite-Na (Na2,Ca)Al2Si4O12•6(H2O) P 6₃/mmc 6/m 2/m 2/m

77.01.02.06a Gmelinite-Ca! (Ca,Na2)Al2Si4O12•6(H2O) P 6₃/mmc 6/m 2/m 2/m

77.01.02.06b Gmelinite-K! (K,Na,Ca)6(Al7Si17O48)•22(H2O) P 6₃/mmc 6/m 2/m 2/m

77.01.02.07 Faujasite-Na (Na2,Ca,Mg)3.5[Al7Si17O48]•32(H2O) F d3m 4/m 3 2/m

77.01.02.07a Faujasite-Ca! (Ca,Na2,Mg)3.5[Al7Si17O48]•32(H2O) F d3m 4/m 3 2/m

77.01.02.07b Faujasite-Mg! (Mg,Na2,Ca)3.5[Al7Si17O48]•32(H2O) F d3m 4/m 3 2/m

77.01.02.08 Levyne-Ca (Ca,Na2,K2)Al2Si4O12•6(H2O) R 3m 3 2/m

77.01.02.08a Levyne-Na! (Na2,Ca,K2)Al2Si4O12•6(H2O) R 3m 3 2/m

77.01.02.09 Tschortnerite! Ca4(Ca,Sr,K,Ba)3Cu3(OH)8[Si12Al12O48]•x(H2O),x>=20 F m3m 4/m 3 2/m

Strunz Class:

09.GD.10 09 - SILICATES (Germanates)

09.G - Tektosilicates with Zeolitic H2O

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

09.GD.10 Chabazite-K! (K2,Ca,Na2,Mg)[Al2Si4O12]•6(H2O) R 3m 3 2/m

09.GD.10 Chabazite-Ca (Ca0.5,Na,K)4[Al4Si8O24]•12H2O P1 1

09.GD.10 Chabazite-Na! (Na2,K2,Ca,Mg)[Al2Si4O12]•6(H2O) R 3m 3 2/m

09.GD.10 Herschelite? (Na,Ca,K)AlSi2O6•3(H2O) R 3m 3 2/m

09.GD.10 Chabazite-Sr! (Sr,Ca,K2,Na2)[Al2Si4O12]•6(H2O) R 3m 3 2/m

09.GD.10 Willhendersonite KCaAl3Si3O12•5(H2O) P1 1

Other Herschelite Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(AntBidBlaNic2) OPTIC PROP.(AntBidBlaNic2)

See Also:

Links to other databases for Herschelite :
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 (UofA)
9 - MinDAT
10 - Mineralienatlas (Deutsch)
11 - Online Mineral Museum
12 - QUT Mineral Atlas
13 - Ruff.Info

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

Herschelite

(Na,Ca,K)AlSi2O6•3(H2O)
Dana No: 77.01.02.02 Strunz No: 09.GD.10
Locality:

Notes: