| Gonnardite | |
|---|---|
 Gonnardite from the Bundoora Quarry, Victoria, Australia. Specimen size 4.9 cm | |
| General | |
| Category | Tectosilicate |
| Formula (repeating unit) | (Na,Ca)2(Si,Al)5O10·3H2O |
| IMA symbol | Gon[1] |
| Strunz classification | 9.GA.05 (10 ed) 8/J.21-40 (8 ed) |
| Dana classification | 77.1.5.7 |
| Crystal system | Tetragonal |
| Crystal class | Scalenohedral (42m) H-M symbol: (4 2m) |
| Space group | I42d |
| Unit cell | a = 13.38 c = 6.66 [Å]; Z = 2 |
| Identification | |
| Color | Colorless, white, yellow or pink to salmon orange |
| Crystal habit | Radiating fibrous; massive |
| Mohs scale hardness | 4 to 5 |
| Luster | Vitreous to silky or dull |
| Streak | White |
| Diaphaneity | Translucent |
| Specific gravity | 2.21 to 2.36 |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 1.514, nβ = 1.515, nγ = 1.520 |
| Birefringence | δ = 0.006 |
| 2V angle | Measured, 52° |
| References | [2][3][4][5] |
Gonnardite is a comparatively rare, fibrous zeolite, natrolite subgroup. Older papers claim that a complete solid solution exists between tetranatrolite and gonnardite, but tetranatrolite was discredited as a separate species in 1999.[6] A series, based on the disorder of the silicon-aluminum in the framework, appears to exist between Na-rich gonnardite and natrolite, Na2(Si3Al2)O10·2H2O.[7]
Gonnardite was named in 1896 after Ferdinand Pierre Joseph Gonnard[8] (1833–1923), who was Professor of Mining Engineering at the University of Lyon, France.
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ "Gonnardite".
- ^ "Gonnardite Mineral Data".
- ^ Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C. (2005). "Gonnardite" (PDF). Handbook of Mineralogy. Mineral Data Publishing. Retrieved 13 March 2022.
- ^ Gaines et al (1997) Dana's New Mineralogy, Wiley
- ^ American Mineralogist (1999) 84: 1445–1450
- ^ Tschernich, Zeolites of the World (1992) Geoscience Press, pages 215 to 225
- ^ "Archived copy". Archived from the original on 2014-07-29. Retrieved 2010-03-30.
{{cite web}}: CS1 maint: archived copy as title (link)