Chabazite

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The chabazite series comprises five mineral species:
Chabazite-Ca: Ca₂[Al₄Si₈O₂₄]. 13H₂O
Chabazite-K: (K₂NaCa_0.5)[Al₄Si₈O₂₄].11H₂O
Chabazite-Mg: (Mg_0.7K_0.5 Na_0.1)[Al₃Si₉O₂₄].10H₂O
Chabazite-Na: (Na₃K)[Al₄Si₈O₂₄].11H₂O
Chabazite-Sr: (Sr,Ca)₂[Al₄Si₈O₂₄]. 11H₂O
These are all tectosilicates (framework silicates), zeolite group
Specific gravity: 2.05 to 2.2 measured, 2.035 calculated
Hardness: 4½
Streak: White
Colour: Colourless, white, yellow, orange, brown
Solubility: Moderately soluble in hydrochloric acid
Environments:

Pegmatites
Basaltic cavities

Chabazite is found in cavities in basalt associated with stilbite, mesolite, mordenite, heulandite and apophyllite; it is also found in pegmatites.
It is a low temperature mineral. Geothermal wells have been drilled through a thick series of basalt flows in western Iceland, where it was found that chabazite crystallised at temperatures from 55^oC to 75^oC at depths between 50m and 400m (ZW).

Localities

At Willy Wally Gully, New South Wales, Australia, chabazite typically occurs alone in vesicles in basalt, but occasionally it is associated with apatite, lévyne-Ca/offretite, phillipsite, aragonite and/or calcite. It is only rarely associated with more than one other zeolite in the same vesicle. (AJM 16.2.81).

At Abbotsford and Bundoora, inner Melbourne, Victoria, Australia, chabazite-(Na) occurs in cavities in basalt associated with gonnardite - natrolite, with ferroan calcite, and with phillipsite (AJM 20.1.38-41).

At Rollinsons Quarry, Victoria, Australia, late forming chabazite-(Ca) was found in some cavities in basalt associated with augite and anorthoclase (AJM 16.2.99).

At the Marron Volcanics of the Olalla Area South-Central British Columbia, Canada, pale orange to pink chabazite rhombohedra to 4 mm across are found with stilbite, laumontite and calcite in the vertical veins cutting the vesicular trachyte in the upper area at Yellow Lake, and pink chabazite crystals associated with heulandite and mesolite are found at a site along the Green Mountain Road to the Apex ski area (R&M 96.520-521).

At Daye county, Hubei, China, chabazite pseudomorphs after gypsum have been found (KL p266).

In Moravia, Czech Republic, chabazite occurs in cavities with axinite, epidote, natrolite, heulandite and stilbite (DHZ 4 p399).

At Palabora, South Africa, chabazite-(Ca) is found associated with analcime, fluorapophyllite and heulandite (R&M 92.5.436).

At the Leveäniemi Mine, Svappavaara, Kiruna, Norrbotten County, Sweden, chabazite has been found with calcite, a stilbite subgroup mineral and diopside (Mindat photo).
Chabazite from the Leveäniemi Mine - Image

At Force Garth Quarry, Forest and Frith, County Durham, England, UK, chabazite occurred as crusts of ill-formed rhombohedra up to 0.5 mm on joint surfaces on blocks of unaltered dolerite (JRS 21.8).

At Cambokeels Mine, Westgate, Stanhope, County Durham, England, UK, interpenetrant rhombohedra of chabazite up to 3 mm across were found as rare associates of analcime and apophyllite. A few specimens composed of crusts of crystalline chabazite on dolerite, unaccompanied by any other mineral, were found in the mine spoil heaps (JRS 21.8).

In Honolulu, Hawaii, USA, chabazite occurs in basaltic cavities with phillipsite, magnetite and calcite (DHZ 4 p399).

At a road cut prehnite occurrence on the Russell-Hermon Road, St Lawrence County, New York, chabazite-(Ca) occurs rarely, associated with quartz and calcite (R&M 87.6.541).

At the Luck Fairfax plant, Fairfax county, Virginia, USA, chabazite has been found as microcrystals associated with stilbite, as yellowish translucent crystals to 2.5 mm in reddish-grey hornfels and as pseudocubic crystals to 3 mm in vugs in dolerite (R&M 98.2.125).

At the Chantilly Quarry, Chantilly, Loudoun county, Virginia, USA, chabazite has been found as white crystals to about 8 mm on prehnite (R&M 98.2.125).

At the Luck Bull Run plant, Conklin, Loudoun county, Virginia, USA, chabazite has been found as white or colourless pseudocubic crystals to 2.5 mm on edge on light green prehnite (R&M 98.2.126).

At the Vulcan Materials Company Crushed Stone Quarry, Manassas, Prince William county, Virginia, USA, chabazite has been found as pale yellow crystals to about 5 mm lining cavities in hornfels (R&M 98.2.125).

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