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| Formula | (Na,Ca0.5,Mg0.5,K)2Al2Si4O12 • 8H2O |
| | Optic class & sign | Isotropic |
| | Relief | Moderate-negative |
| | Refractive Index | 1.466 -1.480
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| | Birefringence | |
| | Colour | Colourless |
| | Zoning | - |
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| Form | Habit | Octahedra |
| | | Surface | |
| | Cleavage | {111} |
| | Twinning | {111}, contact and penetration twins |
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| Reaction textures | |
| | Alteration / decomposition | Faujacite is itself a product of palagonization |
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| Occurence | Ign | |
| | | Met | |
| | | Sed | Authigenic |
| | | Hyd | Vesicle fillings in basalt and phonolite; hydrothermally altered granitic and metamorphic rocks; hydrous alteration of volcanic rocks and pyroclastic material |
| | | Other | |
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| Distinctive properties | Isotropy, habit and twinning; rare zeolite
Note: Reliable identification of zeolite species may require chemical analysis, X-ray diffraction, and/or DTA |
| | Additional comments | n-Δn chart: Anl – analcime, Cbz – chabazite, Fau – faujasite, Gis - gismondine,
Gme – gmelinite, Hrm – harmotome, Php – phillipsite, Wrk - wairakite |
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