Gobbinsite Mineral Data
General Gobbinsite Information
Chemical Formula:
(Na2,Ca)2K2Al6Si10O32•12(H2O)
Composition:
Molecular Weight = 1,339.93 gm
Potassium 6.13 % K 7.38 % K2 O
Sodium 4.29 % Na 5.78 % Na2 O
Calcium 1.79 % Ca 2.51 % CaO
Aluminum 12.48 % Al 23.59 % Al2 O3
Silicon 20.96 % Si 44.84 % SiO2
Hydrogen 1.81 % H 16.13 % H2 O
Oxygen 52.54 % O
______ ______
100.00 % 100.24 % = TOTAL OXIDE
Empirical Formula:
Na2.5 Ca0.6 K2.1 Al6.2 Si10 O32 •12(H2 O)
Environment:
Formed from sodium rich fluids, in basalts and related igneous rocks.
IMA Status:
Approved IMA 1982
Locality:
Basalt cliffs near Hills Port, south of the Gobbins area, County Antrim, Northern Ireland. Link to MinDat.org Location Data.
Name Origin:
Named for the locality.
Name Pronunciation:
Gobbinsite + Pronunciation
Synonym:
ICSD 30975
PDF 35-559
Gobbinsite Image
Images:
Gobbinsite Crystallography
Axial Ratios:
a:b:c =1.0307:1:1.0374
Cell Dimensions:
a = 10.1027, b = 9.8016, c = 10.1682, Z = 1; V = 1,006.88 Den(Calc)= 2.21
Crystal System:
Orthorhombic - Pyramidal H-M Symbol (mm2) Space Group: P mn21
X Ray Diffraction:
By Intensity(I/Io ): 3.201(1), 4.116(1), 7.11(1),
Physical Properties of Gobbinsite
Cleavage:
None
Color:
Lemon white, Chalky white, Light brown.
Density:
2.147
Diaphaneity:
Transparent to Translucent
Fracture:
Brittle - Generally displayed by glasses and most non-metallic minerals.
Habit:
Aggregates - Made of numerous individual crystals or clusters.
Habit:
Lath - Shaped like a small, thin plaster lath, tabular (rectangular) in shape.
Hardness:
4 - Fluorite
Luster:
Vitreous (Glassy)
Streak:
white
Optical Properties of Gobbinsite
Gladstone-Dale:
CI meas = -0.004 (Superior) - where the CI = (1-KPDmeas /KC ) CI calc = 0.025 (Excellent) - where the CI = (1-KPDcalc /KC )
KPDcalc = 0.222,KPDmeas = 0.2285,KC = 0.2277 Ncalc = 1.49 - 1.5
Optical Data:
Biaxial (-), a=1.489, b=1.489, g=1.494, bire=0.0050, 2V(Calc)=0, 2V(Meas)=0.
Calculated Properties of Gobbinsite
Electron Density:
Bulk Density (Electron Density)=2.17 gm/cc note: Specific Gravity of Gobbinsite =2.15 gm/cc.
Fermion Index:
Fermion Index = 0.01 Boson Index = 0.99
Photoelectric:
PEGobbinsite = 2.09 barns/electronU=PEGobbinsite x r electron = 4.53 barns/cc.
Radioactivity:
GRapi = 89.22 (Gamma Ray American Petroleum Institute Units)
Concentration of Gobbinsite per GRapi unit = 1.12 (%)
Estimated Radioactivity from Gobbinsite - barely detectable
Gobbinsite Classification
Dana Class:
77.01.03.04 (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) Im3 m 4/m 3 2/m
77.01.03.09a Paulingite-Na ! (Na2,K2,Ca,Ba)5Al10Si35O90•45(H2O) Im3 m 4/m 3 2/m
77.01.03.09b Paulingite-Ca ! (Ca,K,Na,Ba)5[Al10Si35O84]•34(H2O) Im3 m 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.GC.05 09 - SILICATES (Germanates)
09.G - Tektosilicates with Zeolitic H2O
09.GC -Chains of doubly-connected 4-membered rings
09.GC.05 Amicite K2Na2Al4Si4O16•5(H2O) I2 2
09.GC.05 Garronite Na2Ca5Al12Si20O64•27(H2O) I 41 /a 4/m
09.GC.05 Gobbinsite (Na2,Ca)2K2Al6Si10O32•12(H2O) P mn21 mm2
09.GC.05 Gismondine Ca2Al4Si4O16•9(H2O) P 21 /c 2/m
Other Gobbinsite 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 Gobbinsite :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Athena
5 - EUROmin Project
6 - Ecole des Mines de Paris
7 - GeoScienceWorld
8 - Google Images
9 - Google Scholar
10 - Handbook of Mineralogy (MinSocAm)
11 - Handbook of Mineralogy (UofA)
12 - MinDAT
13 - Mineralienatlas (Deutsch)
14 - Online Mineral Museum
15 - QUT Mineral Atlas
16 - Ruff.Info
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Gobbinsite
(Na2,Ca)2K2Al6Si10O32•12(H2O)
Dana No: 77.01.03.04 Strunz No: 09.GC.05
Locality:
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