Mineral Information and Data:

Gonnardite
(Na,Ca)2(Si,Al)5O10 • 3H2O [CNMNC approved formula]

Named for Ferdinand Gonnard, French mineralogist, Lyons, France, who first noted the mineral. First published in 1896. Redefined 1999 with IMA approval (American Mineralogist, Volume 84, pages 1445–1450, 1999)

IMA status : Redefined IMA Approved; 1999 ()
CLASSIFICATION 
Dana
(8th edition) :
77.01.05.07  
  (77) Tectosilicate Zeolite group
  (77.01) true zeolites
  (77.01.05) Natrolite and related species
  
Nickel-Strunz
(10th edition) :
09.GA.05
  (09) Silicates
  (09.G) Tektosilicates with Zeolitic H2O
  (09.GA) Zeolites with T5O10 Units - The Fibrous Zeolites
  
Crystal system: Tetragonal System
Point group (H-M): 42m (or 4 2m) — scalenohedral
Space group: I42d
Unit cell: a = 13.21(1)Ã…, c =6.622(4)Ã…; Z =2
Crystal Habit: Fibrous crystals, at the centers of radiating spherulites, to 3 cm; massive.
  
Color: White, yellowish to salmon-red
Diaphaneity: Translucent
Luster: Silky
Hardness (Mohs): 5
Measured Density: 2.25 - 2.36 g/cm3
  
Geologic Setting: In cavities in basalt, leucite tephrite, and altered skarn.
Mineral Association: Zeolites, calcite.
  

 

Gonnardite
White blocky terminated prismatic crystals of gonnardite to 8 mm in length are thickly covering the top of a fibrous greenish-brown crystalline aegirine matrix with minor analcime in association.
Origin: Poudrette quarry, Mont Saint-Hilaire, Rouville Co., Québec, Canada.
Sample size: 6.6 x 3.6 x 4.3 cm
Photo: Dan Weinrich

 

Gonnardite
(zoom-in of above)

<<< BACK TO MINERAL SEARCH