Garronite is a series with end members:
Garronite-Ca: Ca3(Al6Si10O32).14H2O
Garronite-Na: Na6(Al6Si10O32).8.5H2O
These minerals are tectosilicates (framework silicates), zeolite group
Specific gravity: 2.13 to 2.18
Hardness: 4½ to 5
Streak: White
Colour: Colourless, white

Basaltic cavities

Garronite is most common in vesicles in basalt and other mafic rocks, often overgrown by or associated with phillipsite, and also as epitaxial overgrowths on phillipsite. At Mont St Hilaire, Canada, it occurs in some metamorphic rocks and in sodalite xenoliths. (Dana)

Back to Minerals