Gonnardite

Gonnardite
Gonnardite from the Bundoora Quarry, Victoria, Australia. Specimen size 4.9 cm
General
CategoryTectosilicate
Formula
(repeating unit)
(Na,Ca)2(Si,Al)5O10·3H2O
IMA symbolGon[1]
Strunz classification9.GA.05 (10 ed)
8/J.21-40 (8 ed)
Dana classification77.1.5.7
Crystal systemTetragonal
Crystal classScalenohedral (42m)
H-M symbol: (4 2m)
Space groupI42d
Unit cella = 13.38
c = 6.66 [Å]; Z = 2
Identification
ColorColorless, white, yellow or pink to salmon orange
Crystal habitRadiating fibrous; massive
Mohs scale hardness4 to 5
LusterVitreous to silky or dull
StreakWhite
DiaphaneityTranslucent
Specific gravity2.21 to 2.36
Optical propertiesBiaxial (+)
Refractive indexnα = 1.514, nβ = 1.515, nγ = 1.520
Birefringenceδ = 0.006
2V angleMeasured, 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.

  1. ^ 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.
  2. ^ "Gonnardite".
  3. ^ "Gonnardite Mineral Data".
  4. ^ 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.
  5. ^ Gaines et al (1997) Dana's New Mineralogy, Wiley
  6. ^ American Mineralogist (1999) 84: 1445–1450
  7. ^ Tschernich, Zeolites of the World (1992) Geoscience Press, pages 215 to 225
  8. ^ "Archived copy". Archived from the original on 2014-07-29. Retrieved 2010-03-30.{{cite web}}: CS1 maint: archived copy as title (link)