Garrawilla Station, Pottinger Co., New South Wales, Australia

(Na,Ca,K,Sr,Ba)₅(Si,Al)₃₆O₇₂ ·24H₂O

Crystal System: monoclinic
Colour: colorless, white, red, yellow, beige, brown or green
Habitus: tabular or prismatic
Hardness: 3-4
Fracture: irregular/uneven, or sub-conchoidal
Density: 2.12-2.35 g/cm³
Origin and geological occurrence: the name “heulandite” indicates a mineral series belonging to the zeolite group. Mineral names of this series have hyphenated suffix indicating the dominant extra-framework cation (e.g., heulandite-Ca, heulandite-Na). These minerals usually occur in vugs of basaltic rocks and, rarely, in metamorphic and sedimentary environments.

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Smorf link

Samples:

9F.10 Heulandite Tabular crystals of heulandite.  #Tectosilicates